Brad gets an allowance of $16 each week, and his younger sister Samantha gets an allowance of $9 each week. Brad saves one-half of his allowance, and Samantha saves two-thirds of her allowance. Suppose Brad started with $0 savings, and Samantha started with $40. How many weeks will it take until they have the same amount in savings?

20 weeks

Step-by-step explanation:

To be able to find the amount of weeks that it will take them to have the same amount, you can say that the amount that Brad saves each week for the number of weeks is equal to the amount that Samantha saves each week for the number of weeks plus the initial amount she has:

(16*1/2)*x=((9*2/3)*x)+40, where

x is the number of weeks

Now, you have to solve for x:

8x=6x+40

8x-6x=40

2x=40

x=40/2

x=20

According to this, the answer is that it will take them 20 weeks to have the same amount in savings.