Rocky mcfist spends a total of $90 per week for karate lessons and ballet lessons. if the amount spent on karate lessons increases $10 per week, it will be two thirds of the amount spent on ballet lessons. how much does rocky spend on ballet lessons?

Let x be the amount of money spent on karate lessons and y be the amount of money spent on ballet lessons (both per week).

1. Rocky Mcfist spends a total of $90 per week for karate lessons and ballet lessons. Then

2. If the amount of money spent on karate lessons increases $10 per week, then it becomes x+10. It will be two thirds of the amount spent on ballet lessons, then

3. Solve the system of equations:

From the second equation

Substitute this expression into the first equation

Then

Rocky spend on ballet lessons $60 per week.

-6 is the correct option from the above given options