how much money is invested altogether

Question

Jeanette invested some money at 4% and twice as much at 5%. if she earns $364 during the year in simple interest, how much money does she have invested altogether

Answer 1

Simple interest:

 

I = PRT

 

x = amount earning 4%

then the amount earning 5% must be 2x.

 

Then

I = x*.04*1 + 2x*.05*1 = 364

 

364 = x(.04 + 2*.05)

364/(.14) = x

2600 = x invested in 4% account

5200 = 2x invested in 5% account

7800 total invested.