Chrystal’s vehicle speed is 30 miles per hour. Ascending the mountain decreases its speed by fifty percent, and descending the mountain increases its speed by twenty percent. If the distance going to the top of the mountain is 60 miles and the distance going down to the foot of the mountain is 72 miles, how many hours will Crystal have to pass the whole mountain?
How fast is the vehicle going when ascending the mountain? ** The vehicle's speed decreases to 30 x 0.50 = <<30*0.50=15>>15 miles per hour when ascending to the top of the mountain.
How many hours will it take to go to the top of the mountain? ** So, the total time Crystal will have to spend going to the top of the mountain is 60 / 15 = <<60/15=4>>4 hours.
How fast is the vehicle going when descending the mountain? ** And the speed of the vehicle increases by 30 x 0.20 = <<30*0.20=6>>6 miles per hour when going down to the foot of the mountain.
How fast is the vehicle going when descending the mountain? ** So, the total speed of the vehicle when going down is 30 + 6 = <<30+6=36>>36 miles per hour.
How many hours will it take to go down the mountain? ** Thus, Chrystal will have to spend 72 / 36 = <<72/36=2>>2 hours to descend from the mountain.
How many hours will it take to pass the whole mountain? ** Therefore, the total hours she will spend to pass the whole mountain is 4 + 2 = <<4+2=6>>6 hours.
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