If both the mean and the standard deviation of 50 observations x1,x2,……,x50 are equal to 16, then the  mean of x1-42,x2-42,…,x50-42 is

Given, mean and standard deviation are equal to 16.∴x1+x2+…x5050=16 and 162=x12+x22…x50250-162⇒2(16)250=x12+x22+….x502 Required mean =x1-42+x2-42+…x50-4250=x12+x22+…+x502+50×16-8x1+x2+…+x5050=162(100)+(50)16-8(16×50)50=400