Mary has a plan to open her own bakery. She needs $67500 of her own money in order to qualify for further financing at her local bank. How long would it take her to have enough money to open her bakery if she invested $42500 now at an annual rate of 7.25% compounded semi-annually?

Okay so for this question the answer is 6 and a half years. I need to know how this is done. The formula for compound interest is
A = P(1 + r/n)^nt, but how do I solve for t?

Question

Mary has a plan to open her own bakery. She needs $67500 of her own money in order to qualify for further financing at her local bank. How long would it take her to have enough money to open her bakery if she invested $42500 now at an annual rate of 7.25% compounded semi-annually?

Okay so for this question the answer is 6 and a half years. I need to know how this is done. The formula for compound interest is 
A = P(1 + r/n)^nt, but how do I solve for t?

luffingsails · Answer

You'll need to use logarithms to solve the equation for t. Can you do that? Or need some help...

anonymous · Answer

I have never learned about logs. Is that the only way to answer this question?

luffingsails · Answer

Yes. You need to know how to use logs... at least on your calculator.

anonymous · Answer

Yes

luffingsails · Answer

The other way, is by substitution... try 1 year... try 2 years and see how much money you have at each point. Trial and error, in other words.

anonymous · Answer

All right thanks for the help. I'll see what I can do.

luffingsails · Answer

Okay, hit me up if you need more help. Good morning.