Question

Kini and Duke are each working during the summer to earn money in addition to their weekly allowance, and they are saving all of their money. Kini earns $9 an hour at her job, and her allowance is $8 per week. Duke earns $7.50 an hour, and his allowance is $17 per week. How many hours do Kini and Duke need to work in order to save the same amount of money in one week?

Answer 1

6 hours

Explanation:

Denote the working time T

=> The amount of money that Kini can save after 1 working week:

A1 = 8 + 9T

=> The amount of money that Duke can save after 1 working week:

A2 = 17 + 7.5T

If Kini and Duke save the same amount of money after 1 working week, then:

A1 = A2

=> 8 + 9T = 17 + 7.5T

=> 9T - 7.5T = 17 - 8

=> 1.5T = 9

=> T = 6

=> By working 6 hours in the 1st week, Kini and Duke will save the same amount of money.