If Rachel purchased a prepaid phone card for $25. Long distance calls cost 24 cents a minute using the card. Rachel used her card only once to make a long distance call. If the remaining credit on her card is $19.24 how many minutes did the call last?

24 minutes

Step-by-step explanation:

25- 19.24= $5.76 used so

$5.76/ 0.24cents = 24 minutes

-2

7 - 9 = -2

reversed:

-2 + 9 = 7

1 number

if we use a graphing calculator, there is only one such number that satisfies the conclusion of the mean value theorem, that is, a number such that

where the right-hand side is the average rate of change of f on the interval [0.5,0.75], which is the slope of the secant line.

in the attached graph, the black line is the secant line which has its slope as the average rate of change of f on [0.5,0.75], while the orange line is the only tangent line to the graph of f in the interval that satisfies the mvt conclusion.