Question

1. The mean of five numbers is 10. If each number is decreased by 3, mean of the new
number is
(a) 13
(b) 10
(c) 7
(d) None of these​

Answer 1

suppose the Number ar

x1 + x2 + x3+X4 + x5/5 = 10

x1 + x2 + x3+X4 + x 5 = 5x10

= 50

by the second condition

( x1 + x2 + x3+X4 + x 5 ) -15=50

x1 + x2 + x3+X4 + x 5 ) = 50+15

= 65

mean = 65 / 5 = 13

Thus the ans is 13