1. The manufacture of particular handmade article takes place in two stages. The time taken for the first stage, say X1, is approximately normally distributed with a mean of 40 min and a standard deviation of 3 minutes. The time taken for the second stage, say X2, is also approximately normally distributed but with a mean of 15 min and a standard deviation of 4 minutes. The times to complete the two stages of production are independently distributed. The mean (i.e. expected value) and standard deviation of the total time, say Y, to manufacture the article are :

A] E(Y)=55 & SD(Y)=25

B] E(Y)=40 & SD(Y)=5

C] E(Y)=55 & SD(Y)=5

D] E(Y)=40 & SD(Y)=25

2 . Again referring to the probability distribution information of above question, the probability of finishing an article is less than 47.5 minutes is approximately

(Hint. Note that the sum of the two normally distributed random variables is also normally distributed)

A]0.0668

B]0.4332

C]0.9332

D]0.1587