Please help! I will award with a medal

Kenneth started saving for retirement at age 40 with plans to retire at age 70. He invested an average of $400 per month in various securities, with an average annual return of 7% adjusted for inflation. Assuming monthly compounding, how much has Kenneth saved at the start of retirement?

I've tried using p(1+r/n)^rt but it doesn't seem to work? Help is greatly appreciated!

Question

Please help! I will award with a medal 

Kenneth started saving for retirement at age 40 with plans to retire at age 70. He invested an average of $400 per month in various securities, with an average annual return of 7% adjusted for inflation. Assuming monthly compounding, how much has Kenneth saved at the start of retirement?

I've tried using p(1+r/n)^rt but it doesn't seem to work? Help is greatly appreciated!

anonymous · Answer

p*((1+r/n)^nt-1)/(r/n). try this 
first check with 1 year and verify the formula

anonymous · Answer

@kristelle

anonymous · Answer

here t=30 and n=12 as it is monthly compounding

anonymous · Answer

Thanks for the help but I already figured it out :)