Answer:
9
Step-by-step explanation:
"For each nickel, she has one dime"
That means she has the same number of nickels and dimes.
"for each dime she has one quarter"
That means she has the same number of quarters and dimes.
She has the same number of each coin.
Let's say she has x coins of each type.
The nickels are worth 0.05x; the dimes are worth 0.10x. The quarters are worth 0.25x. Altogether, the coins are worth
0.05x + 0.10x + 0.25x
We are told her coins are worth $1.20, so we set those two amounts equal and solve for x.
0.05x + 0.10x + 0.25x = 1.20
0.40x = 1.20
x = 1.20/0.40
x = 3
She has 3 coins of each type. Since there are 3 types of coins, she has 9 coins.