Answer
$\frac{3}{4}$
Work Step by Step
We know that $probability=\frac{\text{number of favorable outcomes}}{\text{number of all outcomes}}$
The number of all outcomes is $50+20+90+40=200$, out of these $20+90+40=150$ correspond to the desirable selection.
Hence here the probability is $\frac{150}{200}=\frac{3}{4}$