Acollege student earned $7200 during summer vacation working as a waiter in a restaurant on the boardwalk at the beach. the student invested part of the money at 10% and the rest at 9%. if the student received a total of $680 in interest at the end of the year, how much was invested at 10% the amount invested at 10% was

The amount invested at 10% was $3200.

Step-by-step explanation:

Since we have given that

Principal amount = $7200

Rate of interest are 10% and 9%.

Total interest = $680

Let the amount invested on 10% be 'x'.

Let the amount invested on 9% be '7200-x'.

According to question, we get that

Hence, the amount invested at 10% was $3200.