The mean of the data x1, x2, x3, …………… x10 is 20 then the mean of (x1 + 4) , (x2 + 4) , (x3 + 4) , …………(x10 + 4) will be a) 20 b) 24 c) 40 d) 10 ( WBBSE – 2019 )

The mean of the data x₁, x₂, x₃, …………… x₁₀ is 20 then the mean of (x₁ + 4) , (x₂ + 4) , (x₃ + 4) , …….(x₁₀ + 4) will be

a) 20 b) 24 c) 40 d) 10

Answer : b) 24

Explaination :

Mean of the data x₁, x₂, x₃, …………… x₁₀ is given by______

Mean = x₁ + x₂ + x₃ + …………… + x₁₀ / 10 = 20

Mean of the data (x₁+4) + (x₂ + 4) + (x₃ + 4) + ……+ (x₁₀ + 4) is given by______

mean = { (x₁ + 4) + (x₂ + 4) + (x₃ + 4) + ……+ (x₁₀ + 4) } / 10

= ( x₁ + x₂ + x₃ + …………… + x₁₀ ) + ( 4+4+4+4+4+4+4+4+4+4 ) / 10

= ( x₁ + x₂ + x₃ + …………… + x₁₀ ) / 10 + ( 4 × 10 ) / 10

= 20 + 4

= 24