Question

I need help with part b, c ii, and d

Answer 1

Recall that:

`\text{average speed=}\frac{total\text{ distance}}{total\text{ time}}.`

(b) Since Marcos traveled for 2 hours and 17 minutes a distance of 155 miles, then Marco's average speed for the 155 miles trip is:

`(155mi)/((2+(17)/(60))h)=(155mi)/((137)/(60)h)=(9300)/(137)miles\text{ per hour}\approx67.89miles\text{ per hour.}`

(c ii) Since Devon also traveled the 155 miles in 2hours and 17 minutes but at a constant speed, then the constant speed at which he traveled is equal to his average speed, which is equal to:

`(155mi)/((2+(17)/(60))h)=(155mi)/((137)/(60)h)=(9300)/(137)miles\text{ per hour}\approx67.89miles\text{ per hour.}`

(d) Marco needs to drive 2 miles in 5 minutes to be able to complete the 155 miles trip in 2 hours and 17 minutes, then he must drive at a constant speed of:

`(2mi)/(5\min )=(2mi)/((5)/(60)h)=(120mi)/(5h)=24\text{miles per hour.}`

Answer:

(b) 67.89 miles per hour.

(c ii) 67.89 miles per hour.

(d) 24 miles per hour.