A high school student was able to save $8000 by working a part-time job every summer. He invested half the money in a money market account and half the money in a stock that paid three times as much interest as the money market account. After a year he earned $560 in interest. What were the interest rates of the money market account and the stock?

Question

anonymous · Answer

lets call the interest rate of the money market $x$  
then the interest rate of the stock is $3x$
you have $4000\times x+4000\times 3x=560$ and you can solve for $x$

anonymous · Answer

you good from there?

anonymous · Answer

first step would be to combine like terms on the left and get $1600x=560$ then divide to get the rate of interest

anonymous · Answer

oops i am off by a zero, should be 
$$16000x=560$$
$$x=560\div16000=.035=3.5\%$$

anonymous · Answer

in addition: The Interest rate in the Money Market Account was _____	%
The Interest rate in the Stock was_____________ %

anonymous · Answer

we solved for "money market" so the answer is $3.5\%$

anonymous · Answer

stock market is 3 times that amount, or $10.5\%$

anonymous · Answer

ist, 3(the anser) so i could get the interrest rate for stck?

anonymous · Answer

@satellite73  thank u. u're a real genius. ur so kind. thanks. =)

anonymous · Answer

yw (blush)