ok or this you want to write a system of equations you know you have quarters=q dimes=d and pennies=p. you know you have 52 all together so you can say
you also know what they are worth
.25q, .1d, .01p
you know the total so each amount times the number of how many you have will give you the total. now your question doesn't seem quite complete I am assuming your total is the cost of the book so you know that
now when you have a problem with 3 variables you need three equations. The third is the stack of coins you know you have 3 and 2 are equal. Now I would have to assume a lot from here I am not sure if by same number you mean the number of coins or the worth of the coins. I also can't quite tell if there is more to the problem than this so if could look and see if there is more and then let me know I can finish up the problem for you, or if this is enough of a start to solve it for you great!