Question

The mean of 15 numbers is 27. If each number is multiplied by 4, what will be the mean of the new numbers?

Answer 1

Given the mean of 15 number is = 27

let the number be x₁,x₂,x₃.............x₁₅

(x₁+x₂+x₃.................+x₁₅) / 15 = 27

(x₁+x₂+x₃.................+x₁₅) = 27 * 15 = 405 ...... eqn first

Now each number is multiplied by 4 then, new set of 15 number is , sothe new mean is

(x₁*4 +x₂*4 +x₃*4 .................,x₁₅*4) / 15 = 4* (x₁+x₂+x₃.................+x₁₅) / 15 = 4*27 = 108 [ using eqn first ]

hence new mean is = 108