Question

Aditya left his house at 9:20 a.m. and travelled at 75 km/hr. His brother left later along the same road at 90 km/hr. They both arrived at the same destination at 3:20 p.m. At what time did Aditya s brother leave home
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Answer 1

Aditya left his house at 9:20 a.m. and travelled at 75 km/hr. His brother left later along the same road at 90 km/hr. They both arrived at the same destination at 3:20 p.m. Then aditya's brother left home at 10:20 am.

Given

• Time when aditya left the home =9:20 am
• Speed of aditya = 75km/hr.
• Time when both reach at destination = 3:30pm

Time taken by aditya = 6hrs (from 9:20 am to 3:20pm)

To calculate distance covered by aditya

$distance = speed \times time \: taken$

• Distance covered by aditya= 75km/hr ×6 hr

=450 km

As both reach same destination :

• Distance covered by aditya's brother =450km

Given

• Speed of aditya's brother =90km/hr.

• To find time taken by aditya's brother

$time \: taken = \frac{distance \: covered}{speed}$

• $time \: taken = \frac{450}{90} = 5hr$
• If Time taken to reach is 5hrs
• Then aditya's brother had started 5 hrs back from 3:20 pm
• So he started journey at 10:20am

To reach on same destination at same time aditya's brother started journey at 10:20 am with speed of 90km/hr.

Answer 2

Answer:

Aditya left his house at 9:20 a.m. and travelled at 75 km/hr. His brother left later along the same road at 90 km/hr. They both arrived at the same destination at 3:20 p.m. Then aditya's brother left home at 10:20 am.

Given

Time when aditya left the home =9:20 am

Speed of aditya = 75km/hr.

Time when both reach at destination = 3:30pm

Time taken by aditya = 6hrs (from 9:20 am to 3:20pm)

To calculate distance covered by aditya

distance = speed \times time \: takendistance=speed×timetaken

Distance covered by aditya= 75km/hr ×6 hr

=450 km

As both reach same destination :

Distance covered by aditya's brother =450km

Given

Speed of aditya's brother =90km/hr.

To find time taken by aditya's brother

time \: taken = \frac{distance \: covered}{speed}timetaken=

speed

distancecovered

Speed of aditya's brother =90km/hr.

To find time taken by aditya's brother

time \: taken = \frac{distance \: covered}{speed}timetaken=

speed

distancecovered

time \: taken = \frac{450}{90} = 5hrtimetaken=

90

450

=5hr

If Time taken to reach is 5hrs

Then aditya's brother had started 5 hrs back from 3:20 pm

So he started journey at 10:20am

To reach on same destination at same time aditya's brother started journey at 10:20 am with speed of 90km/hr.