real life functions

1. RATIONAL FUNCTIONS
QUARTER I – MODULE 2: LESSON 1 – (REAL LIFE FUNCTIONS)

2. AT THE END OF THE LESSON,YOU ARE EXPECTED TO:
•determine rational functions, and
• solve real-life situations involving rational functions.

3. RATIONAL FUNCTION
It is a function in the form

4. SOLVING RATIONAL FUNCTION (WORD PROBLEM)
EXAMPLE # 1:
Martin can finish a job in 6 hours working alone.Victor has
more experience and can finish the same job in 4 hours
working alone. How long will it take both people to finish that
job working together?

5. PROBLEM # 1

10. PROBLEM # 2
Sarah can finish a job in 7 hours working alone. If Sarah and
Matteo work together, they can finish the work in 3 hours.
How long will it take if Matteo will choose to work alone?

11. STEP 1. UNDERSTANDTHE PROBLEM.
Step 1: State the given.
Given: Sarah = 7 hours
Matteo = x hours (we can assign this as x as it is unknown)
Together = 3 hours

12. STEP 2. CHANGETHE GIVENTO RATES
Rates: Sarah =
Matteo =
Together =

13. STEP 3.ADD THE TWO RATES AND EQUATE TOTHE
RATE THAT THEY WORK TOGETHER
𝐸𝑞𝑢𝑎𝑡𝑖𝑜𝑛:
1
7
+
1
𝑥
=
1
3

14. STEP 4: PUTTHEVALUE WITHOUTVARIABLE TO
THE OTHER SIDE.

15. STEP 5: EXPRESS ANSWER IN A SENTENCE
It will take 5.25 hours to finish the job if Matteo chooses
to work alone

16. ACTIVITY 1: DIRECTIONS: SOLVE EACH PROBLEM
1. One person can complete a task in 8 hours.Another person can
complete a task in 3 hours. How many hours does it take for them to
complete the task if they work together?
2. Sigfried can paint a house in 5 hours. Stephanie can do it in 4 hours.
How long will it take the two working together?

17. ACTIVITY 1: DIRECTIONS: SOLVE EACH PROBLEM
3. Joy can pile 100 boxes of goods in 5 hours. Stephen and Joy can
pile 100 boxes in 2 hours. If Stephen chooses to work alone, how
long will it take?
4. Computer A can finish a calculation in 20 minutes. If Computer
A and Computer B can finish the calculation in 8 minutes, how
long does it take for the Computer B to finish the calculation
alone?