Given:
The sum of measures of A and B is 90°
so, we have the following equation:

And, A is 30° less than twice B
so, we have the following equation:

Solving the equations (1) and (2)
Substitute with A from equation (2) into equation (1)

Substitute with B into equation (2) to find A:

So, the answer will be:
The measure of angle A = 50
The measure of angle B = 40