Use the probability distribution graph to answer the question. P(X≤a)=0.75 I got 3, can someone please check my work?

Step-by-step explanation:

For any continuous probability distribution, the total area under the curve indicating the probability density function must be 1.

is saying that the area to the left of  is 0.75. This area is also that of a rectangle.

The height of this rectangle is 0.25, and , which means the width is 3. Since 4 - 1 = 3, it must be that .