Question

You have been saving nickels, dimes, and quarters in a jar for about a year. You decide to see how much money you've saved up. When you get everything counted it turns out you have 361 total nickels, dimes, and quarters worth a total of $41.45. You think is is odd that you have exactly twice as many dimes as quarters. Find the number of each coin. Number of Nickels: Number of Dimes: Number of Quarters:

Answer 1

Answer:

x = number of nickels = 127

y = number of dimes = 156

z = number of quarters = 78

Step-by-step explanation:

Let

x = number of nickels

y = number of dimes

z = number of quarters

Total worth of the coins = $41.45

Total number of coins = 361

x + y + z = 361 (1)

dime = $0.1,

nickel = $0.05

quarter = $0.25

0.05x + 0.1y + 0.25z = 41.45 (2)

twice as many dimes as quarters.

y = 2z

Substitute y = 2z into (1) and (2)

x + 2z + z = 361

0.05x + 0.1(2z) + 0.25z = 41.45

x + 3z = 361

0.05x + 0.2z + 0.25z = 41.45

x + 3z = 361 (3)

0.05x + 0.45z = 41.45 (4)

Multiply (4) by 20

x + 3z = 361 (3)

x + 9z = 829 (5)

Subtract (3) from (5)

9z - 3z = 829 - 361

6z = 468

Divide both sides by 6

z = 468 / 6

= 78

z= 78

Recall,

y = 2z

= 2(78)

= 156

y = 156

Substitute the value of y and z into

x + y + z = 361

x + 156 + 78 = 361

x + 234 = 361

x = 361 - 234

= 127

x= 127

x = number of nickels = 127

y = number of dimes = 156

z = number of quarters = 78