Answer:
a is the middle point on x-axis = 3
Explanation:
On probability distribution graph, P(x≥a) means area under the curve from x=a to x=6.
On a probability distribution graph, the entire area under curve =1
But we are given that P(X≥a) is 0.5 which is half of 1.
And we are given with a normal distribution graph which has center at x=3.
Hence half of the area means area from x=3 to x=6 which is nothing but P(X≥3).
Therefore a is 3.
We can also check it by finding area under curve from x=3 to x=6.
Area under curve from x=3 to x=6 can spitted into a rectangle and a triangle.
Rectangle area = (5-3)X0.2=0.4
Triangle area=
Hence total area from x=3 to x=6 is 0.4+0.1=0.5