mischiefmanaged wrote:
warriorguy wrote:
Total Distance = Speed * Time = 30 * 2 = 60 kms
Let the speed of the child be x
Relative speed = 30 + x
Time = \(\frac{Distance}{Speed}\)
\(\frac{7}{4}\) = \(\frac{60}{(30+x)}\)
x= \(\frac{30}{7}\) = 4.28
Can someone please explain, how is time 7/4?
Normally it takes 120 mins for Anwar but this time it took 105 mins that is 7/4 hours.
However, as per my understanding the equation should be as below in the context of relative speed.
\(t=\frac{d}{s}\)
here t is the time at which Anwar meets his son, d is the distance between them and s is their relative speed, i.e, speed of Anwar plus his son's
Normally, it takes 2 hours for Anwar with the speed of 30 km/hr to do a round trip. From this it can be derived that round trip distance is 60 km and the distance between anwar and his son d =30 km
When it took 105 mins for Anwar to complete his trip, he met his son at 105/2= 52.5 mins = 7/8 hrs
Considering the speed of Anwar's son as x, the relative speed is 30 + x
The above equation becomes,
\(\frac{7}{8}=\frac{30}{(30+x)}\)
\(x=30/7=4.28 km/hr\)
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