The list below shows all of the possible outcomes for flipping four coins. hhht hhth hhtt hthh htht htth httt thhh thht thth thtt tthh ttht ttth what is the probability of getting the same number of heads and tails?

I'm at a bookstore with $\$35$ in my pocket and a $20\%$-off coupon. what is the cost of the most expensive book i can buy with my money and the coupon? (assume that there are books of every possible price in the bookstore. it's a large bookstore! )