Question

The postal service offers flat-rate shipping for priority mail in special boxes. Today, Kylie shipped 4 small boxes and 4 medium boxes, which cost her $88 to ship. Meanwhile, Trevor shipped 9 small boxes and 4 medium boxes, and paid $123. How much does it cost to ship these two sizes of box? Shipping costs $ for a small box and $ for a medium box.

Answer 1

Answer:

Shipping Cost of small boxes = x = $7

Shipping Cost of large boxes = y = $15

Step-by-step explanation:

Let us represent

Shipping Cost of small boxes = x

Shipping Cost of large boxes = y

The postal service offers flat-rate shipping for priority mail in special boxes.

Today, Kylie shipped 4 small boxes and 4 medium boxes, which cost her $88 to ship.

4x + 4y = 88...... Equation 1

Meanwhile, Trevor shipped 9 small boxes and 4 medium boxes, and paid $123.

9x + 4y = 123 ..... Equation 2

Combining both Equations

4x + 4y = 88...... Equation 1

9x + 4y = 123 ..... Equation 2

Subtract Equation 1 from Equation 2

5x = 35

x = 35/5

x = $7

Solving for y using Equation 1

4x + 4y = 88...... Equation 1

4($7) + 4y = 88

28 + 4y = 88

4y = 88 - 28

4y = 60

y = 60/4

y = $15

Shipping Cost of small boxes = x = $7

Shipping Cost of large boxes = y = $15