7. Chanda wants to put 150 square metres of garden at her backyard. This is the maximum area of garden she can have. She wants to have a rectangular area of garden with length one metre
less than 3 times the
width. Find the length and width to the nearest tenth of a metre.

There are three bags: a (contains 2 white and 4 red balls), b (8 white, 4 red) and c (1 white 3 red). you select one ball at random from each bag, observe that exactly two are white, but forget which ball came from which bag. what is the probability that you selected a white ball from bag a?