penny weighs 2.5 grms & a nickel weighs 5 grms. If 27 pennies & nickels weigh 117.5 grms

Question

Please help do not understand!

Looking for : , what is the value of the change?

Answer 1

Let's x=number of pannies, and y=number of nickels

x+y=27

2.5x+5y=117.5

Now you need to solve this system of two equations.

x=27-y

2.5(27-y)+5y=117.5

67.5-2.5y+5y=117.5

2.5y=50

y=20

x=27-20=7

total: 1 dollar and 7 cents.

7 pennies =7 cents

20 nickels= 1 dollar