Marcello drew a triangle ABC, Angle A was twice as large as Angle B, Angle C was 15 degrees less than ten times Angle B. How many degrees is each angle?

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

a is the right answer

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