The arithmetic mean is 12 and the number of observations are 20 then the sum of all of the values id a.) 8 b.) 1667 c.) 32 d.) 240

The sum of the values is C.)32

Step-by-step explanation:

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

x

step-by-step explanation: