mean and standard deviation

[ranjankumarnayak5]

[Var1995]

after solving for Z u will get Z= (X+20)/5. now use the formulae: E(aX+ b)= aE(X)+ b. here, a=1/5 n b= 4 ; for SD(aX+ b)= |a| SD(X). u will get b as the ans.