Question

Maria has $10,000 to invest in two accounts.he decides to invest one part in an account with 5% interest and the rest in an account with 8% interest. At the end of the year he has earned $702,50 in interest.¿how much did maria invest in the 8% account?

Answer 1

Answer: she invested $3250 in 5% interest account and $6750 in 8% interest account.

Explanation:

Let P be the amount Maria invested in an account with 5% interest , then 10,000-P denote the amount invested in account with 8% interest.

The simple interest on amount P with rate r % in time t is given by:-

`I=P(r)/(100)t`

Interest in 5% account in 1 year=
`P((5)/(100))(1)=0.05P`

Similarly,

Interest in 8% account in 1 year=
`(10,000-P)((8)/(100))(1)=800-0.08P`

According to the question,

`0.05P+800-0.08P=702.50\\\Rightarrow-0.03P=702.50-800\Rightarrow\ -0.03P=-97.5\\\Rightarrow\ P=(97.5)/(0.03)\\\Rightarrow\ P=3,250\\\\10,000-3250=6750`

Thus, she invested $3250 in 5% interest account and $6750 in 8% interest account.