contestada

Ivan drove to the mountains last weekend. There was heavy traffic on the way there, and the trip took 7 hours. When Ivan drove home, there was no traffic and the trip only took 4 hours. If his average rate was 27 miles per hour faster on the trip home, how far away does Ivan live from the mountains? Do not do any rounding.

Respuesta :

Answer:252 miles

Explanation:

Given

During his way to mountain it took 7 hr to drive

and during his return trip it took 4 hr to return

Let x be the distance between home and mountain

average speed for return is  27 miles per hour faster than his former trip

let v be the speed on his way to mountain thus v+27 is his return speed

thus [tex]7=\frac{x}{v}[/tex]----1

for return trip

[tex]4=\frac{x}{v+27}[/tex]-----2

divide  1 & 2

[tex]\frac{7}{4}=\frac{x\cdot (v+27)}{v\cdot x}[/tex]

[tex]7v=4v+4\cdot 27[/tex]

[tex]3v=4\cdot 27[/tex]

[tex]v=36 mph[/tex]

thus [tex]x=7\times 36=252\ miles[/tex]