Question: A construction firm finally has got their order from an internet shop-4 identically looking boxes. In the first box there are 7 tool kits for electricians and 9 tool kits for plumbers. In the second box there are 5 tool kits for electricians and 8 tool kits for plumbers. In the third box-6 tool kits for electricians and 7 tool kits for plumbers; and in the fourth-10 tool kits for electricians and 3 tool kits for plumbers.From a randomly chosen box one electrician's tool kit was taken. What is the probability that mentioned tool kit was taken from the third box?