Hello Steve, it didn't work for "t" i can't get the actual value...

Question

Find the time required for an investment of 1 dollars to grow to 7200 dollars at an interest rate of 7.5 percent per year, compounded quarterly

Answer 1

7200=1(1+ .075/4)^t/4 where t is in years.

You actually want one dollar to grow to 7500?

take log of each side

log 7200=t/4 (log 1.018)

t=4* log7200/log1.018=1991 years

Answer 2

Hello Bobpursley, it still didn't work. it says wrong answer. Thanks

Answer 3

^4t not to the t/4

1.01875^4t = 7200

4 t = log 7200/log 1.01875

t = 120 years

Answer 4

Hello Damon, thanks a lot. But it says incorrect.