Amodel builder has 30 pieces of balsa wood in a box. four pieces are 15 in lon, 10 pieces are 12 in long, and the rest are 8 in long, what is the probability the builder will pull an 8inch piece from the box without looking?

We know that

total pieces of balsa wood in a box > 30
pieces 15 in lon> 4
pieces 12 in lon> 10
pieces 8 in lon> (30-(10+4))=16

Let
P--->the probability the builder will pull an 8 inch piece from the box without looking
P=(pieces 8 in lon)/(total pieces)=16/30=0.5333=53.33%

the answer is 53.33%