Ms. Kincaid keeps a supply of dimes and quarters in her car to pay for highway tolls. A week’s supply of toll coins contains 5 more dimes than quarters and totals $4.00. How many quarters does Ms. Kincaid spend on highway tolls in one week

A. 10
B.15
C.16
D.40

Respuesta :

Answer: (A) 10

Step-by-step explanation:

                Value       Quantity     =  TOTAL Value

dimes:        .10            Q + 5        =    .10(Q = 5)

quarters:    .25               Q           =      .25Q


Dimes + Quarters = $4.00

.10(Q + 5) + .25Q = 4.00

.10Q + .50 + .25Q = 4.00

           .50 + .35Q = 4.00

                    .35Q = 3.50

                          Q = 10

Quarters = 10

Dimes = Q + 5

           = 10 + 5

           = 15

Answer: Option A, she has 10 quarters.

Step-by-step explanation:

We have quarters of $0.25 and dimes of $0.10

We have 5 more dimes than quarters and a total of $4.00

How many quarters Ms. Kincaid has?

Q is the number of quarters and D the number of dimes.

We have the system of equations:

D = Q + 5

Q*$0.25 + D*$0.10 = $4.00

First, we can replace the first equation into the second and solve it for Q.

Q*$0.25 + (5 + Q)*$0.10 = $4.00

Q*($0.25 + $0.10) + $0.50 = Q*($0.35) + $0.50  = $4.00

Q = (4.00 - 0.50)/0.35 = 3.50/0.35 = 10

So she has 10 quarters.

The correct option is A.