Question

A collection of 54 coins is worth $3.90. The collection contains only nickles and dimes Let n represent the number of nickles and let d represent the number of dimes.
How many of each type of coin are in the collection

Answer 1

OK. So. we know that there is a total of $3.90
A dime is worth $0.10 and a nickle is worth $0.05
So, yo need to make a simple equation here.
Im not gonna give you the answer, just tell u how to do it. 
Just tell me what you get in the comments.