Pearl deposited $60 into a savings account for which interest is compounded monthly. According to the rule of 72, what interest rate will cause her money to double in approximately 33 years?

A. 0.6%
B. 0.5%
C. 1.8%
D. 2.2%

Question

Pearl deposited $60 into a savings account for which interest is compounded monthly. According to the rule of 72, what interest rate will cause her money to double in approximately 33 years?

 		A.	0.6%
 		B.	0.5%
 		C.	1.8%
 		D.	2.2%

anonymous · Answer

@perl

perl · Answer

so we can divide the given interest rates.
72 / .6
72/ .5
72/1.8
72/2.2

perl · Answer

72/2.2  = 32.7272 ~ 33 
so its D

anonymous · Answer

oooooooooohhhhh ok thanks @perl