If 1,a,5 and 15 are in proportion ,find the value of a​

a=3

Step-by-step explanation:

Given :

1:a :: 5: 15

To find a

a=15×1/5

a=3

Therefore, value of a =3

the answer to the question is a  

it has the same slope and the same y-intercept.

answer: expected value of x = 1.0

step-by-step explanation:

p(x=0) = 0.25

p(x=1) = 0.50

p(x=2) = 0.25

expected value for x = 0×0.25 + 1×0.5 + 2×0.25 = 1.0