Question

System of Equations : Money

Damian has been saving coins he finds on the ground for several months. So far he has found 37 coins that are either pennies or nickels. The combined value of his found pennies and nickels currently is $1.09. What is the system of linear equations, written using standard form, represents the situation if Damian found p pennies and n nickels.​

Answer 1

18 nickles 19 pennies

Explanation:

value of 1 penny=$0.01

value of 1 nickle=$0.05

0.01p+0.05n=1.09

p+n=37

there are two methods for this system

I.substitution

p+n=37

p=37-n

we replace p in the first relation

0.01(37-n)+0.05n=1.09

0.37-0.01n+0.05n=1.09

0.04n=0.72

n=18 nickels

p+18=37

p=37-18=19 pennies

II.reduction

0.01p+0.05n=1.09

p+n=37

we multiply the second equation by 100

p+5n=109

p+n=37

we calculate the difference between the two relations

p-p+5n-n=109-37

4n=72

n=18

p+18=37

p=19