Jenny has a total of 21 dimes and quarters in her piggy bank. if the coins are worth $4.50, how many quarters does she have?

Jenny has 5 dimes and 16 quarters.

Step-by-step explanation:

Let number of dimes and quarters are d and q in the piggy bank of Jenny.

"Jenny has total 21 dimes and quarters in her piggy bank".

By the first statement

d + q = 21  ------(1)

Second statement is "The coins are worth $4.50. or 450 cents"

1 dime = $0.10 or 10 cents,   1 quarter = $0.25 or 25 cents

10d + 25q = 450

2d + 5q = 90 ------(2)

Now we multiply equation 1 by 2 and subtract it by equation 2

(2d + 5q) - 2(d + q) = 90 - 2×21

2d + 5q - 2d - 2q = 90 - 42

3q = 48

q =

  = 16

Now we put q = 16 in equation number (1)

d + 16 = 21

d = 21 - 16

d = 5

Therefore, Jenny has 5 dimes and 16 quarters.

look a the sides they are perpendicular

a

explanation: