There are 21 coins only two tyoes which are:(quarter and nickel) they add up to 2.45 how many of each coins are there

Answer 1

First, we need to create equations that represent the situation. Let's use Q for quarters and N for nickels.

One Quarter = $0.25

One Nickel = $0.05

Equations:

N + Q = 21

$0.05(N) + $0.25(Q) = $2.45

N= 21-Q

Q= 21-N

You can plug in any of the equations into the second one I provided so you can determine how many quarters or nickels you will have.

$0.05(21-Q) + $0.25Q = $2.45

$0.05 x 21 = $1.05 - $0.05Q + $0.25Q = $2.45

Add and subtract accordingly.

$0.20Q = $1.40

$1.40/$0.20 = 7 Quarters

Then plug in the 7 for Q in the second equation again.

$0.05(N) + $0.25(7) = $2.45

$0.05N + $1.75 = $2.45

$0.05N = $0.70

$0.70/$0.05 = 14 Nickels

14 Nickels + 7 Quarters = 21 coins (to check your work).