Answer:
Option C. 4 nickels and 5 quarters
Step-by-step explanation:
let the number of nickels = x, and the number of quarters = y
Derrick has a total of 9 nickels and quarters in his pocket
So, x + y = 9
∴ y = 9 - x ⇒(1)
1 nickel = 5 cent = $0.05
1 quarter = 25 cent = $0.25
The total amount of money he has in coins is $1.45
So, 0.05 x + 0.25 y = 1.45
Multiply the both sides by 100
∴ 5x + 25y = 145 ⇒(2)
Substitute with y from (1) at (2)
∴ 5x + 25(9-x) = 145
Solve for x
5x + 225 - 25x = 145
-20x = 145 - 225 = -80
x = -80/-20 = 4
Substitute with x at (1)
y = 9 - 4 = 5
So, The number of nickels = 4 , and the number of quarters = 5
The answer is option C. 4 nickels and 5 quarters
