Question

The sales totals at Robert's food store have increased linearly over the month. Which of these best shows the sales in the first three months?

$1200 in the first month, $1212 in the second month, $1224.12 in the third month

$1200 in the first month, $1236 in the second month, $1273.08 in the third month

$1200 in the first month, $1285.48 in the second month, $1370.96 in the third month

$1200 in the first month, $1224.28 in the second month, and $1248.48 in the third month

Answer 1

1200 in the first month, $1285.48 in the second month, $1370.96 in the third month

Explanation:

Answer 2

Answer: $1200 in the first month, $1285.48 in the second month, $1370.96 in the third month

Step-by-step explanation:

We know that when a function increases linearly, then the rate of change of function over time remains constant.

• $1200 in the first month, $1212 in the second month, $1224.12 in the third month

Here,
`1212-1200=12` but
`1224.12-1212=12.12`

⇒ Rate of change is not constant.

• $1200 in the first month, $1236 in the second month, $1273.08 in the third month

Here,
`1236-1200=36` but
`1273.08-1236=37.08`

⇒ Rate of change is not constant.

• $1200 in the first month, $1285.48 in the second month, $1370.96 in the third month

Here,
`1285.48-1200=85.48` and
`1370.96-1285.48=85.48`

Thus, the rate of change is constant i.e. $85.48 per month.

Hence, This shows the sales in the first three months.

• $1200 in the first month, $1224.28 in the second month, and $1248.48 in the third month

Here,
`1224.28-1200=24.28` but
`1248.48-1224.28=24.2`

⇒ Rate of change is not constant.