Question

A building contractor buys 60​% of his cement from supplier A and 40​% from supplier B. A total of 95​% of the bags from A arrive​ undamaged, and a total of 75​% of the bags from B arrive undamaged. Find the probability that an undamaged bag is from supplier A.

Answer 1

Answer: 0.665.

Explanation:

60% of the bags are from supplier A, and 95% of them are undamaged.

40% of the bags are from supplier B, and 75% of them are undamaged.

Then, the number of undamaged bags from supplier A is:

0.6*0.95 = 0.57 or 57%

from B is:

0.4*0.75 = 0.3 or 30%

This means that the percentage of undamaged bags is:

57% + 30% = 87%.

Then, the probability that an undamaged bag is from supplier A is equal to the percentage of undamaged bags that came from supplier A (57%) and the total percentage of undamaged bags (87%) this is:

P = 57%/87% = 0.655 or 65.5%

Then the probability that an undamaged bag comes from supplier A is 0.665.