Question

Marcelo jogs at a speed of 7 miles per hour when there are no hills. He plans to jog up a mountain road which will cause his speed to decrease by r miles per hour. Which of the following expressions represents the time, t, in hours it will take him to jog 13 miles up the mountain road?

a. t=13/7r
b. t=7+r/13
c.t=13-r/7
d. t=13/7+r

Answer 1

The time it will take Marcelo to jog 13 miles up the mountain road can be found using the formula t=d/r, where t is the time, d is the distance, and r is the speed. The correct expression for the time it will take him to jog 13 miles up the mountain road is t=13/(7-r).

Step-by-step explanation:

The time it will take Marcelo to jog 13 miles up the mountain road can be found using the formula t=d/r, where t is the time, d is the distance, and r is the speed. Since Marcelo's speed is initially 7 miles per hour and decreases by r miles per hour, his speed up the mountain road will be 7-r miles per hour. Therefore, the correct expression for the time it will take him to jog 13 miles up the mountain road is t=13/(7-r).