Ialwaysneedhelp111
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- Sep 7, 2019
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Mr Whippy drove 120 km from Dublin to Newry. On the return trip, he drove 10 km/h slower than on the outward trip. If the return journey was 10 minutes longer, find his outward and inward speeds.Mr Whippy drove 120 km from Dublin to Newry. On the return trip, he drove 10 km/h slower than on the outward trip. If the return journey was 10 minutes longer, find his outward and inward speeds. I’ve tried so many different variations but none are correct. The answers are 90km/h and 80km/hView attachment 14040
Thank you so muchMr Whippy drove 120 km from Dublin to Newry. On the return trip, he drove 10 km/h slower than on the outward trip. If the return journey was 10 minutes longer, find his outward and inward speeds.
Let the
outward speed = O kmph
inward speed = I kmph = (O - 10) kmph
Time to travel outward = 120/O
Time to travel inward = 120/I = 120/(O-10)
Then we know: If the return journey was 10 minutes longer
120/(O-10) - 120/O = 1/6
Now solve for "O" from above and then solve for "I".
I was just wondering. Why does this not work for distance / time ? Why do you have to do distance / speed ?Mr Whippy drove 120 km from Dublin to Newry. On the return trip, he drove 10 km/h slower than on the outward trip. If the return journey was 10 minutes longer, find his outward and inward speeds.
Let the
outward speed = O kmph
inward speed = I kmph = (O - 10) kmph
Time to travel outward = 120/O
Time to travel inward = 120/I = 120/(O-10)
Then we know: If the return journey was 10 minutes longer
120/(O-10) - 120/O = 1/6
Now solve for "O" from above and then solve for "I".