Abook is on sale for $8.93. the sale price is 15% off the original price. what was the
original price?

i think 10.30 according to my calculation

the sum of all the angles in a triangle are equal to 180

so you can add   the 3 given angles together to equal 180:

5y + 2y + 2y = 180

or since all three angles have the same letter, combine the 3 angles to equal 180:

9y = 180