Question

An online store that sells baseballs and bats offers free shipping on any order of $20 or more. The baseballs cost $1 each and the bats cost $8 each. The inequality below shows the number of baseballs and bats that a person can buy to get free shipping.

Answer 1

Inequality given:

$x+8y\ge20$

where x = baseballs and y = bats.

To know which ordered pair (x,y) is a solution, we have to try with every pair and see if the condition meets.

• (0,3)

$\begin{gathered} 0+8\cdot3\ge20 \\ 24\ge20 \end{gathered}$

As this condition is true, then (0,3) is a solution.

• (2,4)

$\begin{gathered} 2+8\cdot4\ge20 \\ 2+32\ge20 \\ 34\ge20 \end{gathered}$

As this condition is true, then (2,4) is a solution.

• (3,2)

$\begin{gathered} 3+8\cdot2\ge20 \\ 3+16\ge20 \\ 19\ge20 \end{gathered}$

As this condition is NOT true, then (3,2) is NOT a solution.

• (4,2)

$\begin{gathered} 4+8\cdot2\ge20 \\ 4+16\ge20 \\ 20\ge20 \end{gathered}$

As the sing also includes number 20, this condition is true, then (4,2) is a solution.

• (6,1)

$\begin{gathered} 6+8\cdot1\ge20 \\ 6+8\ge20 \\ 14\ge20 \end{gathered}$

As this condition is NOT true, then (6,1) is NOT a solution.

• (6,3)

$\begin{gathered} 6+8\cdot3\ge20 \\ 6+24\ge20 \\ 30\ge20 \end{gathered}$

As this condition is true, then (6,3) is a solution.

Answer:

• (0,3)

,

• (2,4)

,

• (4,2)

,

• (6,3)