Answer:
20 weeks
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.