Question

HCT buys red and blue pens in the ratio 1:2. The college has three suppliers for these [4] pens. Supplier A provides 70% of the red pens and 40% of the blue pens. The remainder of the red pens come from supplier B and the remainder of the blue pens come from supplier C. The college knows that 20% of the pens supplied by A, 15% of those supplied by B, and 10% of those supplied by C are defective. The pens are all stored together in a box. A member of the staff takes a pen at random.
a) Find the probability that the pen will be defective.
b) The member of the staff found that the pen was defective and immediately complained about the quality of pens from supplier A. See whether he is justified by finding the probability that the defective pen was from A.

Answer 1

Soin a plepetwe) = are on the content content the ting = 1 +0.15 +04 = 0.155 3 Everytime, we first select probability of colourl of pin (13 or 2) then the probability whether it is from A, Borc then finally the probability that it is defective b) please en) - PC belen is from A given) p/pen is from A and it is defective P (it is defective) = Yo 0-$55 = 100 = 30 ^ 0-645 Since probability is 70.5, he is justified to do so