Bob makes his first $ 1, 100 deposit into an ira earning 6.8 % compounded annually on his 24th birthday and his last $1, 100 deposit on his 36th birthday (13 equal deposits in all). with no additional deposits, the money in the ira continues to earn 6.8 % interest compounded annually until bob retires on his 65th birthday. how much is in the ira when bob retires?

$133991.2

Step-by-step explanation:

Bob makes his first $1000 deposit into an IRA earning 6.8% compounded annually on his 24th birthday and his last $1000 deposit on his 36th birthday (13 equal deposits in all).

Therefore, till his retirement on his 65th birthday, the first deposit of $1000 will compound for (65 - 24) = 41 years.

His second deposit of $1000 will compound for 40 years and so on up to his 13th deposit of $1000, which will be compounded for ( 65 - 36) = 29 years.

Therefore, after retirement in his IRA there will be total

$ dollars

= $

So, this is a G.P. whose number of terms is 13, the first term is and common ratio is 1.068, then using formula for sum of G.P. we get,

= $

= $

= $133991.2 (Answer)

n=9

step-by-step explanation:

7 times a number = 7n

decreased by 13 = 7n-13

same as is =

5 times the number = 5n

increased by 5 = 5n+5

7n-13 = 5n+5

2n=18

n=9