This equation makes it able for you to plug-and-play the numbers. Let\'s classify the variables first. n is the number of people p is the profit acquired If you plug in p=0 (the situation when the profit is 0), you get 0 = 10(120-n)-50n Now all you have to do is solve for n. Solution This equation makes it able for you to plug-and-play the numbers. Let\'s classify the variables first. n is the number of people p is the profit acquired If you plug in p=0 (the situation when the profit is 0), you get 0 = 10(120-n)-50n Now all you have to do is solve for n..