Assistance with an algebra question

Question

The angles of a triangle add up to 180 degrees. The second angle is 20 degrees larger than the smallest, the third angle is two times as big as the smallest. Find the measure of the smallest angle in degrees

Answer 1

a=20+b

c=2b

a+b+c=180

20+b+b+2b=180

4b=160

b=40 degrees