Question

Peggy had four times as many quarters as nickels. She had $2.10 in all. How many nickels and how many quarters did she have?

Answer 1

let's let q = # of quarters and n = # of nickels

"four times as many quarters as nickels" ---> so q = 4n
"She had $2.10 in all." ---> since each quarter is worth $0.25, (q) quarters are worth 0.25q
same logic with nickels, 0.05n

so 0.25q + 0.05n = 2.10

solve for q (would recommend solving q = 4n for n in terms of q, then plugging it into the second equation, to solve for q)