Answer:
a. 550-8t
b. 454 dollars
Explanation:
a. Calling t the number of weeks, the balance in the first account is
(400-40t)(400−40t)
while the balance in the second account is
(150+32t)(150+32t)
So, the total amount in both accounts is the sum of the balances of the two accounts:
(400-40t)+(150+32t)=(400+150)+(-40t+32t)=550-8t(400−40t)+(150+32t)=(400+150)+(−40t+32t)=550−8t
b. To find the total amount in both accounts after 12 weeks, we just need to substitute t=12 into the total balance, and we find:
550-8t=550-8\cdot 12=550-96=454550−8t=550−8⋅12=550−96=454