How much did Mr. Coupon invest in each account?

Question

Mr. Coupon has $5000 to invest. He splits the money into an ira and 403b, which have a return of 3% and 6% respectively. If he earns $240 total after one year, how much did mr. Coupon invest into each account?

Answer 1

a + b = 5000 ---> a = 5000 - b

0.03a + 0.06b = 240

 

0.03(5000 - b) + 0.06b = 240

150 - 0.03b + 0.06b = 240

0.03b = 90

b = 3000

 

a = 5000 - 3000

a = 2000