4 + 18 + 10 + 8 = 40, this means that the piggy bank has 40 coins in total. Probability of the FIRST coin being a dime is 18/40 and the probability of the SECOND coin being a dime too is 17/39. To find the answer you would multiply 18/40 x 17/39.
The answer is a 8 days. the equation say's at the beginning of the day he read's 50 page's and later read's 14. this is everyday so. add 50+14+64. divide 400 by 64 and you get 7.8125, round that up and you get 8<span />