its 30 because if you add the numbers together then you get 90, then you do 180-90 and get 90, divide 90 by 3 and get 30
Answer:

Step-by-step explanation:
Cross multiply, isolate the variable, and divide by the coefficient to solve.

Plug back in to check.

16 1/10
Because you have 15 and then for 22/20 it is a improper fraction so take 20 away from it to get 2/10 then add 1 to 15 for 16 and then simplify 2/20 to 1/10