Question 346531
By definition, 
{{{A+B=180}}}
.
.
{{{B=2A-15}}} (I think you meant 15 degrees and not 150 degrees)
Substitute,
{{{A+(2A-15)=180}}}
{{{3A-15=180}}}
Solve for {{{A}}}, then go back and solve for {{{B}}}.