This document contains a solved practice test for a recruitment exam for BREB with 40 multiple choice questions (MCQs) covering general knowledge and aptitude, and 8 numerical/conceptual questions. It provides the questions, solutions, reasoning, and key data for each problem. The author requests feedback be provided if any mistakes are found.

1. This solution is done by
Engr. Md. Al-amin, ME, BUET.
(Obviously with the help of some talented people)
If any mistake/wrong solution is found please feel free to comment/discuss at alaminbuet2008@gmail.com
BREB Recruitment exam (8th
June 2018)
MCQ(Q-1~Q-20: GK types, Q-21~Q-30: Aptitude types): 20*1+10*2 = 40 Marks
1.what's type of reactor will use in rooppur nuclear power plant ? VVER-1200/523, VVER-
1200/521, VVER-1000/523, VVER-1000/521
2. Types of transponder of bangabandhu satellite-1 ? 26(ku-band) & 14(c-band), 24(ku-
band) & 16(c-band), 16(ku-band) & 24(c-band), 14(ku-band) & 26(c-band)
3. If length of a wire is 0.1% increased, resistance will be increased by? 0.2%, 0.3%, 0.4%,
0.5%
4. If distance between sun and earth decreased by half, how many days will make a year?
130, 139, 125, 129
Ans:
We know,
Kepler third law, T2
= R3
T2
=
√(R2)3
T1 √(R1)3
Or,
T2
=
√(R/2)3
T1 √(R)3
Given Data
T1=365 days
R1 = R
T2=?
R2 = R/2
T2= T1 / 2√2 = 365/ 2√2 = 129 days
5. Aspect ratio of a TV screen is 16:9 (width: height), if perimeter of screen is 100, calculate
width of screen ?
2(16x+9x) = 100
Or, x = 2
Width = 9x = 9 x 2 = 18
6. If 5 tickets are sold in price of 3 tickets, what's the amount saved while buying them?
33.33%, 66.66%----- -----
7. If regular price of a book is of 20% discount of its original price and on an occasion 15%
discount is given on regular price, what's the actual discount? 20%, 30%, 32%, 38%
If original price is 100 tk then,
100( 1-0.2) x (1-0.15) = 68 tk , discount = 100 – 68 = 32 %
8. Google's actual company name is- Google Inc, Google Corporation, ------------ , ----------

2. This solution is done by
Engr. Md. Al-amin, ME, BUET.
(Obviously with the help of some talented people)
If any mistake/wrong solution is found please feel free to comment/discuss at alaminbuet2008@gmail.com
9. An object of 1000 kg entered earth, earth radius 6400 km, gravity 9.81, with what velocity
the object will hit earth? 11.2 Km/s, 12.2 km/s, 12 km/s, 11 km/s
10. A rectangle's length is thrice its width & perimeter is 36 m then find the width?
9 m, 4.5 m, 10 m, 18 m
2(x+3x) =36 or x= 4.5 m, width = 4.5 m
11. There were 8 girls, 20 boys on Thursday Next day girls joined twice the boys left, now
girl: boy ratio is 4:1, how many boys left Thursday?
12, 6, 11, 9
12. নিচের ক োিনিচে অসমোি েতো আচে ? কেোমরো বোনি এচে আনম রওিো নিব।
13. ‘’আমোর নিের বোনিচর অন্তচর অন্তচর আচেো েুনম হৃিয় জুচি’’ – এই গোচির রনেয়েো ক ? Rudra
Mohammad Shahidullah
14. The longest sea bridge of world connected three countries: Hong Kong-Zhuhai-Macau
15. The opposition if word "Suffrage" ?
16. “PLAY WITH AN OPEN HEART” a slogan from which country in world cup FIFA
2018 ?
17. সনি সনি নবচেি ক োিনি ? ন ম+িু ে = ন ম্ভুে
Departmental + (Epic)Written(Q-31~38): 40 Marks
31. Calculate PH
value for 2% NAOH solution.
Ans:
We know,
Concentration, S=[OH-
]=
1000𝑊
𝑀𝑉
=
1000 𝒙 2
40 𝒙 100
= 0.5 M
again, POH
= - log [OH-
] = - log [0.5] = 0.301
We have, PH
+ POH
= 14
PH
= 14 - POH
= 14 - 0.301 = 13.699
Given Data
2% NaOH ~ 2gm NaOH in
100 ml solution
hence,
W= 2 gm
V = 100 ml
MNaOH = 23+16+1 = 40
Concentration,S=[OH-
]=?
PH
= ?

3. This solution is done by
Engr. Md. Al-amin, ME, BUET.
(Obviously with the help of some talented people)
If any mistake/wrong solution is found please feel free to comment/discuss at alaminbuet2008@gmail.com
32. a) Determine the area enclosed by y=x2
, x axis, x=1, x=3 lines.
Ans:
From figure, let f(x) = y = x2
& g(x) = y=0
limiting functions, x=1, x=3
By integration,
Area = ∫ {𝑓(𝑥) − 𝑔(𝑥)}𝑑𝑥
𝑥=3
𝑥=1
= ∫ {x^2 − 0}𝑑𝑥
𝑥=3
𝑥=1
= ∫ x^2𝑑𝑥
𝑥=3
𝑥=1
= [
𝑥3
3
]1
3
= [
33
3
] - [
13
3
] =
27
3
-
1
3
=
𝟐𝟔
𝟑
b) A car running at 72km/h and taking U turn in 4 sec. what is the acceleration of the car?
Ans:
Acceleration while taking U-turn,
a = v2
/r
= 202
/25.464
= 15.07 m/s2
Given Data
V = 72 Km/hr = 72 x 1000/3600
= 20 m/s
t = 4 sec
distance travelled, s = vt = 20 x
4 = 80 m
again , s=rꝊ
hence, r = s/Ꝋ = 80/π = 25.464
m
33. a) Steel pipe of 120mm dia rests horizontally having temp of 25 degree Celsius, K=0.05
W/m.k, nusselt number =30, calculate heat transfer coefficient.
Ans:
We know,
Nusselt number,
Nu = h Lc / K
h = Nu.K / Lc
= 30 x 0.05 / 0.12
= 12.5 W/m2
. K
Given Data
Lc= Characteristic length=
hydraulic dia for pipe=
4A/P = 4 x (πD2
/4)/ πD =
D=120 mm = 0.12 m
T= 25+273=298 K
K=0.05 W/m.k
Nu = 30
h= ?

4. This solution is done by
Engr. Md. Al-amin, ME, BUET.
(Obviously with the help of some talented people)
If any mistake/wrong solution is found please feel free to comment/discuss at alaminbuet2008@gmail.com
b) Sum of two numbers is 20, If cube of one number multiplied by other is a maximum,
calculate the two numbers.
Ans:
x+y=20 ----(1) and x3
y is maximum
Now take the value of y from equation (1).
= x3
(20-x)= 20x3
-x4
Now differentiate in terms of x and putting it equal to 0 which is the slope of the graph at the
maxima or minima
0=60x2
- 4x3
, which gives x = 0 or 15
as if x = 0 here comes minima thus x = 15 which makes the numbers as 15 & 5
34.a) A gas with 27 degree Celsius temperature, atmospheric pressure, suddenly compressed
to half of its original volume, calculate final temperature and pressure.
Ans:
Sudden compression = isentropic process
T2 / T1 = (V1/ V2)(γ-1)
T2 = T1 x (V1/ V2)(γ-1)
=
300 x (V/ 0.5V)(1.4-1)
=
300 x (2)0.4
=
395.85 K
Again,
P2 / P1 = (V1/ V2)γ
P2= P1 x (V1/ V2)γ
= 101325 x (V/ 0.5 V)1.4
= 101325 x (2)1.4
= 267398.3 Pa
Given Data
T1 =27+273= 300 K
P1 = 101325 Pa
V1= V (let)
V2= 0.5V
T2 =?
P2 = ?
γ = 1.4
b) Single point cutting tools having Taylor Exponent 0.25, if cutting speed is halved, what
will be the tool life?
Ans:
We have,
Taylor’s equation for tool life expectancy ,
VTn
= C
which gives us,
V1 T1
n
= V2 T2
n
or T2 = T1 x (V1/ V2)(1/n)
= T x (V/ 0.5V)(1/0.25)
= T x (2)(1/0.25)
= 16T
So, cutting speed is halved then tool life will be increased by
16th
times
Given Data
n= Taylor exponent = 0.25
V1 =cutting speed= V (let)
T1 = tool life= T (let)
V2 = 0.5 V
T2 = ?

5. This solution is done by
Engr. Md. Al-amin, ME, BUET.
(Obviously with the help of some talented people)
If any mistake/wrong solution is found please feel free to comment/discuss at alaminbuet2008@gmail.com
35.a) A pump having head of 50 m, flow rate 60 liter/sec. if the suction line is 100 m long &
diameter 100 mm, pump has overall efficiency of 70%, the find power required to drive the
pump. f=0.003
Ans:
we know,power ,
p =
𝛾𝐻𝑄
𝜂
p =
9.81𝑥1000𝑥50.40475𝑥0.06
0.7
= 42.383 KW
we know, Q =AV
V=Q/A=Q/(πD2
/4)
=0.06/[π(0.1)2
/4)] = 0.764 m/s
Total head =H+Hd+Hf
= H+
𝑣2
2𝑔
+
4𝑓𝑙𝑣2
2𝑔𝑑
= 50+
(0.764)2
2𝑥9.81
+
4𝑥0.003𝑥100𝑥(0.764)2
2𝑥9.81𝑥.1
= 50+0.2975+0.375= 50.40475m
Given Data
H = 50 m
Q = 60 liter/sec =
0.06 m3
/s
l=100m
d=100 mm=0.1 m
ηpump = 70% = 0.7
f=0.003
power, P = ?
b) Automobile engine has weight of 240 Kg, rested on four springs, front spring has spring
constant of 16 MN/m, other springs having 32 MN/m. Find frequency at which resonance
will occur.
Ans:
We know, frequency
at which resonance
will occur,
f=
1
2𝜋
√
𝐾
𝑚
=
1
2𝜋
√
96 𝑥 106
240
= 100.618 Hz
Given Data
m= 240 Kg
K=Equivalent spring
constant
= Kf1+ Kf2+ Kb1+ Kb2
= 16+16+32+32
= 96 MN/m
f= ?
36.a) A tyre is designated 145/70 R 12 69 S. What do you understand by "145/70 R" ?
Ans:
145/70 R means ,
 The section width or thickness
of tyre from shoulder to
shoulder is 145 mm.
 The aspect ratio is 70%, aspect
ratio is defined as the ratio of
section height to section width
of the tyre. In this case it means
section height is 70% of
section width I,e. 101.5 mm.
 R represents that the tyre is
radial.

6. This solution is done by
Engr. Md. Al-amin, ME, BUET.
(Obviously with the help of some talented people)
If any mistake/wrong solution is found please feel free to comment/discuss at alaminbuet2008@gmail.com
b) A hydroelectric turbine having head of 24.5 m, flow rate 10 m3
/s, efficiency 90% and
speed 4 rps, which type of turbine to be used.
Ans:
We know, turbine power
Pturbine = γHQη = 9.81 x 1000 x 24.5 x 10 x 0.9 = 2163.105 KW
Again turbine specific speed,
Ns =
N√P
=
240√2163.105
= 204.78
(H)(5/4)
(24.5)(5/4)
Given Data
H=24.5 m
Q = 10 m3
/s
η = 90 % = 0.9
N = 4 x 60 rpm = 240 rpm
Types of turbine = ?
As specific speed is between 50~250 so Francis turbine should be used.
37 .a) Solid circular shaft having diameter 60 mm & torque 2000 Nm. Find maximum
shearing stress in that shaft ?
Ans:
We know,
τmax =
16T
=
16 x 2000
πD3
π x (.06)3
= 47.156 Mpa
Given Data
D = 60 mm = 0.06 m
T = 2000 N-m
τmax = ?
b) In a coal fired power plant boiler consuming feed water 215 Kg per hour, having enthalpy
change of 150 KJ/Kg, having coal consuming rate 50Kg/hour (data may differ) , coal having
calorific value of 2000 KJ/Kg. Find boiler efficiency.
Ans:
We know,
ηBoiler
=
ms (h-hf1)
mf . C
=
215 x 150
50 x 2000
Given Data
ms=Mass of water evaporated into
steam = 215 Kg/hr
mf = Mass of fuel used = 50Kg/hr
Change of enthalpy = enthalpy of
steam – enthalpy of feed water
=h-hf1 = 150 KJ / Kg
C= Calorific value of fuel = 2000
KJ/Kg
Boiler efficiency, ηBoiler = ?
= 32.25 %