a jar contains n nickles and d dimes. there are 20 coins in the jar, and the total value of the coin is $1.40. how many nickels and how dimes are in the jar?

Question

 creating systems of linear equation

Answer 1

set up a system of equations

 

n + d = 20

 

.05n + .10d = 1.40

 

use the Substitution Method

 

n = 20 - d

 

.05(20 - d) + .10d = 1.40

 

multiply both sides by 100

 

5(20 - d) + 10d = 140

 

100 - 5d + 10d = 140

 

100 + 5d = 140

 

5d = 40

 

d = 8

 

n = 20 - 8 = 12

 

there are 8 dimes and 12 nickels