Problema Solution
John can jog twice as fast as he can walk. He was able to jog the first 11.5 miles to his grandmother's house, but then he tired and walked the remaining 2.5 miles. If the total trip took 2.75 hours, then what was his average jogging speed?
Answer provided by our tutors
Let
v = the walking speed
2v = jogging speed
d1 = 11.5 mi
d2 = 2.5 mi
t = 2.75 hr
Since speed = distance/time follows time = distance/speed:
d1/(2v) + d2/v = t
11.5/(2v) + 2.5/v = 2.75
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click here to see the equation solved for v
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v = 3 mph
2v = 2*3 = 6 mph
John's jogging speed was 6 mph.