Question

System: Answer: 9. Fadi has 35 dimes and nickels in his pocket. When he added up how much money he had it totaled $2.50. Write a system of equations to determine how many nickels and how many dimes are in his pocket.

Answer 1

Answer:

The system of equations is:

d + n = 35...........................(1)

0.1d + 0.05n = 2.50.......(2)

There are 20 nickels and 15 dimes in his pocket

Explanations:

Let the number of dimes he has be d

Let the number of nickels he has be n

The total number coins he has = 35

d + n = 35........(1)

Note that:

1 dime = $0.1

1 nickel = $0.05

The total amount of money he had = $2.50

0.1d + 0.05n = 2.50.......(2)

The system of equations is therefore:

d + n = 35...........................(1)

0.1d + 0.05n = 2.50.......(2)

Make d the subject of the formula in equation (1)

d = 35 - n..........(3)

Substitute equation (3) into equation (2)

0.1 (35-n) + 0.05n = 2.50

3.5 - 0.1n + 0.05n = 2.50

3.5 - 0.05n = 2.50

0.05n = 3.5 - 2.5

0.05n = 1.0

n = 1.0/0.05

n = 20

Substitute the value of n into equation 3

d = 35 - n

d = 35 - 20

d = 15

There are 20 nickels and 15 dimes in his pocket