If the average of a and b is 45, and the average of b and c is 35, then (a-c)=?

A 5

B 10

C 20

D 30

Solution

Correct Answer: Option C

here, a+b/2=45 or,a+b=90 again, b+c/2=35 or,b+c=70 so, a+b-b-c=90-70=20