Answer:
3/4 or 0.75
Explanation:
You have four options available
Lets say P(A) is pick a rocket
P(A) = 2/4 because there are two rockets in the four choices
simplify it to 1/2
P(B) pick a big = 2/4 because there are two bigs and two smalls.
simplify it to 1/2
P(A ∩ B) = Pick a big rocket = 1/4
P(AUB) = P(A)+P(B)- P(A ∩ B)
P(AUB) = 1/2+1/2- 1/4 = 3/4 or 0.75