Question

Charlie paid $660 for 6 shirts and 4 belts. One shirt costs three times as much as one belt. If Sam bought 5 such shirts and 2 such belts, how much would he have to pay?

Answer 1

Sam would pay $510.

Explanation:

In order to solve this problem we will attribute variables to the value of shirts and belts, we will call the shirts "x" and the belts "y". We know that the total amount paid for 6 shirts and 4 belts was $660, so we have:

6*x + 4*y = 660

We also know that one shirt cots three times more as one belt, so we have:

x = 3*y

With these two equations we can calculate the price of each item, we do that by using the expression for "x" from the second equation on the first one, as shown below:

6*(3*y) + 4*y = 660

18*y + 4*y = 660

22*y = 660

y = 660/22 = 30

x = 3*30 = 90

So if Sam bought 5 shirts and 2 belts we have:

amount paid = 5*x + 2*y = 5*90 + 2*30 = 450 + 60 = 510

Sam would pay $510.

Answer 2

$510

Explanation:

Let the cost for a shirt be s and the cost for a belt be b

Charlie Paid $660 for 6 shirts and 4 belts.

• 6s+4b=660

One shirt costs three times as much as one belt.

• s=3b

Substituting s=3b into the first equation

6s+4b=660

6(3b)+4b=660

18b+4b=660

22b=660

b=$30

s=3X30=$90

If Sam bought 5 such shirts and 2 such belts

This is modelled as: 5s+2b

Since:

• Cost of one shirt, s=$90
• Cost of one belt, b=$30

The cost of 5 such shirts and 2 such belts=5(90)+2(30)=$510