Question

To build a concrete column in a building, the amount of bricks needed is 29.5 kg with standard deviation of 3 kg. You need to build 50 columns. (The variation is due to the random volume of the bricks)

a. What is the probability that the total amount of bricks needed for the 50 columns is greater than 1500 kg

b. What is the probability that 2400 kg of bricks is enough to complete 70 or more columns

c. The engineer wants to reduce the mean amount of bricks needed per column so the probability of completing 70 or more columns using 2400 kg is 0.99. Assume that the standard deviation remains 3 Kg

Answer 1

From the given data

(a)

  

(b)

  

(c)