Word problem, algebra.

Question

You invested $7000 between two accounts, paying 7% and 8% annual interest, respectively.If the total interest earned that year was $520, how much was invested at each rate?

Answer 1

Interest = Principle * Rate * Time

 

In this case, you split the $7000 principle into two sums, x and $7000-x.  You invest x at 8% and $7000-x at 7%. Express the percents as decimals:

 

Interest = x*(0.08)*(1 year) + (7000-x)*(0.07)*(1 year)

 

$520 = 0.08x + $490 - 0.07x

 

$30 = 0.01x

 

Solve for x (the amount invested at 8%).  Once you have x, the amount invested at 7% is $7000-x.