Answer
3
Work Step by Step
$P(x \geq a) = 0.5$
$P(x \geq a) = ∫_{a}^{∞} f(x).dx$
= $∫_{a}^{∞} \frac{1}{d-c}.dx$
= $∫_{a}^{∞} \frac{1}{2}.dx$
= $∫_{a}^{4} \frac{1}{2}.dx + $∫_{4}^{∞} \frac{1}{2}.dx$
= 1/2 (4-a) + 1/2 (0)= (4-a)/2
Since $P(x \geq a) = 0.5$
(4-a)/2 = 0.5
4-a = 1
a = 3
