Question

Ximena has procrastinated all her homework until the very last minute. She has 2 hours to spare until midnight, which is when all her homework is due. Her English homework will take 30 more minutes than her Biology homework, and her Math homework will take three times as long as her Biology homework. How long will each subject take?

Answer 1

English: 48 minutes

Math: 54 minutes

Biology: 18 minutes

Explanation:

Set up each subject with the variable x as the biology homework.:

English: (x+30)

Math: (3x)

Biology: (x)

Now add them together and set it equal to 120 (2 hours into minutes):

x + 30 + 3x + x = 120

Move 120 over to the left and simplify:

5x - 90 = 0

Solve:

5(x - 18) = 0

x - 18 = 0

x = 18

So biology is 18 minutes, and then plug 18 in for all the other subjects:

English: 18+30=48 minutes

Math: 3*18=54 minutes

Biology: 18 minutes