Shona is buying a rug for her room. store a has the rug for $45 with a 10% discount. store b has the same rug for $46 and is offering a $10 off coupon. the sales tax is 6% on either purchase. if shona only has $40 to spend, which store will she purchase the rug from, and how much will she have left over?

Anew 2-lane road is needed in a part of town that is growing. at some point the road will need 4 lanes to handle the anticipated traffic. if the city's optimistic estimate of growth is used, the expansion will be needed in 4 years and has a probability of happening of 40%. for the most likely and pessimistic estimates, the expansion will be needed in 8 and 15 years respectively. the probability of the pessimistic estimate happening is 20%. the expansion will cost $ 4.2 million and the interest rate is 8%. what is the expected pw the expansion will cost?