+18 Karlee invests $200 a month starting when she is 16 and continues for 10 years. At this time she does
not invest any more money, but the money is reinvested at the same rate and continues earning
interest. Chase invests $200 a month starting when he is 25. Assuming the interest rate is 8%
compounded monthly for each investment, who will have more money at age 65? How much more?
+118608 I get Karlee has $825 544.94 and Chase has $702 856.25
I got the formula off the net
\(r=\frac{8\%}{12 }= 0.08/12 = 0.00\dot 6 \\ P=200\\ \text{n = number of months.} \)
See if you can take if from there.
k
+36915 Using the formula that Melody posted.... I get Karlee has ( r = .006666667 I think this is where our answers differ) 894,064.89
and Chase has 702 856.24
+118608 No that is not why our results differ. Your r is the same as mine, you, or rather your calculator, has just rounded off r.
BUT it would not make THAT mcuh difference.
You have to use 2 formulas for Karlee.
First the Future value of an annuity due (120 months), and then the compound interest formula (12*39 months)
+36915 Hey Melody.... I didn't round...... the diff was my mistake using Kaylee's 10 year balance for 40 years ( SHOULD be 39) ....should have re-read the Q ! 
+118608 The inominative interest rate rate is 8% p.a or 0.08% pa
\(\frac{0.08}{12} = 0.00\dot 6\) per month
+36915 Yah....didn't see the little dot above the 6 ...I am more accustomed to a bar...though I have seen the dot before...
