4. Incorrect. The answer is false not true. If we calculate the definite integral between 0 and 0.5, then we will have that:
6 [1/2x 2 |00.5] - 6 [ 1/3 x 3 |00.5] = 6[1/8 - 1/24] = 0.5.
So, the oil company will discover crude oil with a 50% of probability.