Bunuel
A rental firm has only two distinct types of vehicles: minivans and sedans. Each vehicle runs on exactly one fuel type, either gasoline or electricity. If a vehicle is selected at random, is the probability that it is a sedan running on electricity greater than the probability that it is a minivan running on gasoline?
(1) The probability that a randomly selected vehicle is either a minivan or runs on gasoline is 2/5.
(2) The probability that a randomly selected vehicle is either a sedan or runs on electricity is 5/8.
Lets call the probability of:
... a sedan = S
... a minivan = M
... runs on electricity = E
... runs on gasoline = G
Additionally, to find the probability of two events occurring together, we multiply their probabilities.
So, probability of a sedan running on electricity = S*E and a minivan running on gasoline = M*G
To find if S*E > M*G
Using (1) alone,
M = 2/5 and G = 2/5
M*G = (2/5)*(2/5)
M*G = 4/25
Since we cannot say if S*E > 4/25 or not, statement (1) alone is not sufficient
Using (2) alone,
S = 5/8 and E = 5/8
S*E = (5/8)*(5/8)
S*E = 25/64
Since we cannot say if 25/64 > M&G or not, statement (2) alone is not sufficient
Using both (1) and (2) together,
We can say that 25/64 > 4/25 is true, hence
(C) Both statements together are sufficient