According to the rule of 72, if Beth invests $200 and $1300 into two separate accounts with the same interest rate, which amount will double faster?

A. $200
B. $1300
C. Both will double at the same rate.
D. None of the above

Question

According to the rule of 72, if Beth invests $200 and $1300 into two separate accounts with the same interest rate, which amount will double faster?

 		A.	$200
 		B.	$1300
 		C.	Both will double at the same rate.
 		D.	None of the above

perl · Answer

this is a good one. i have to recall rule of 72 (and 70). it is the amount of time it takes to double an account

perl · Answer

according to wiki 
if you were to invest $100 with compounding interest at a rate of 9% per annum, the rule of 72 gives 72/9 = 8 years required for the investment to be worth $200; an exact calculation gives ln(2)/ln(1+.09) = 8.0432 years.

anonymous · Answer

thanks so much @perl

perl · Answer

Both will double at the same rate.