The credit remaining on a phone card (in dollars) is a linear function of the total calling time made with the card (in minutes). The remaining credit after 23 minutes of calls is $16.78 , and the remaining credit after 54 minutes of calls is $12.44 . What is the remaining credit after minutes of calls?

Step-by-step explanation:

let x represent the number of minutes of call.

Let y represent the remaining credit after x minutes of call.

If we plot y on the vertical axis and x on the horizontal axis, a straight line would be formed. The slope of the straight line would be

Slope, m = (12.44 - 16.78)/(54 - 23)

m = - 4.34/31 = - 0.14

The equation of the straight line can be represented in the slope-intercept form, y = mx + c

Where

c = intercept

m = slope

To determine the intercept, we would substitute x = 54, y = 12.44 and m = - 0.14 into y = mx + c. It becomes

12.44 = - 0.14 × 54 + c

12.44 = - 7.56 + c

c = 12.44 + 7.56

c = 20

The linear function becomes

y = - 0.14x + 20

d. millimeters per hour.

step-by-step explanation:

we are given that,

carlo used a rain gauge to measure the amount of water his lawn is receiving from the sprinklers.

since, according to the options, we see that,

water cannot be measured by 'miles per hour', 'meters per second' and 'grams per seconds'.

we get that, the water can be measured by 'millimeters per hour'.

hence, the appropriate rate for describing the amount of water is 'millimeters per hour'.

50-38=12

step-by-step explanation: