Answer: The answers are (3). $3744, (4). $8464.50, (5). $62060.
Step-by-step explanation: The calculations are as follows :
(3) Here, P = $1200, r% = 4%, T=3 years.
Therefore, Simple Interest is given by

So, the amount of money Ben will have at the end of third summer will be

Thus, the amount is $3744.
(4) Here, P = $2700, r% = 4.5%, T=3 years.
Therefore, Simple Interest is given by

So, the amount of money Josh will have at the end of third summer will be

Thus, the amount is $8464.5
(5) Here, P = $14500, r% = 7%, T=4 years.
Therefore, Simple Interest is given by

So, the amount of money Emily will have at the end of fourth year will be

Thus, the amount is $62060.