Question

Pudge had 2.25 in dimes and nickles. if he had twice as many dimes as nickles. how many of each coin did he have

Answer 1

First, write an equation system based on the problem
For an instance, d stands for the number of dimes and n stands for the number of nickels. Dime's worth $0.10 and nickel's worth 0.05

"Pudge had 2.25 dimes and nickels" could be written as
⇒ 0.10d + 0.05n = 2.25  (1st equation)

"He had twice as many dimes as nickels" could be written as
⇒ d = n   (2nd equation)

Second, solve the equation system
Substitute d as n from the second equation to the first equation to find the number of nickels
0.10d + 0.05n = 2.25
0.10n + 0.05n = 2.25
0.15n = 2.25
n = 2.25/0.15
n = 15

Because d = n, therefore d = 15

Pudge has 15 coins of dimes and 15 coins of nickels