Posted by tasha on Thursday, February 19, 2009 at 9:32am.
find out how long it takes a $2700 investment to double if it is invested by 7% compounded semiannually. Round to the nearest tenth of a year . Use the formula A=P[1+r/n]^nt

mathhelp solve please  bobpursley, Thursday, February 19, 2009 at 9:38am
2=(1+.07/2)^2t
log of both sides..
log2=2t log(1+.035)
can you do that? Solve for t? 
mathhelp solve please  Reiny, Thursday, February 19, 2009 at 9:39am
you want the $2700 to double, so A = 5400
5400 = 2700(1 + .035)^(2t)
2 = 1.035^(2t)
I hope you know how to use logs and know the rules of log operations
2t = log 2/log 1.035
2t = 20.148
t = 10.07
= 10.1 to the nearest tenth 
mathhelp solve please  tasha, Thursday, February 19, 2009 at 9:55am
how did you get (.035)

mathhelp solve please  bobpursley, Thursday, February 19, 2009 at 10:12am
seven percent/n= .07/2