Aptitude - Time and Distance - Discussion

Discussion Forum : Time and Distance - General Questions (Q.No. 11)
11.
In covering a distance of 30 km, Abhay takes 2 hours more than Sameer. If Abhay doubles his speed, then he would take 1 hour less than Sameer. Abhay's speed is:
5 kmph
6 kmph
6.25 kmph
7.5 kmph
Answer: Option
Explanation:

Let Abhay's speed be x km/hr.

Then, 30 - 30 = 3
x 2x

6x = 30

x = 5 km/hr.

Discussion:
211 comments Page 22 of 22.

Asritha lalam said:   4 weeks ago
Here's Step by step explanation of the solution:

The Distance is equal for both --> D = 30 km,
Let the time taken by Sameer (T)= x.
So, time taken by Abhay = x+2 --> (2hrs more than sameer).

We know Distance and Time, so we can calculate speed i.e S=D/T.
Let the speed of Abhay (S) = 30/x+2-->[1]

Given that,
if Abhay doubles his speed --> new speed of Abhay = 2s.
He will take 1hr less than sameer --> now time taken by Abhay = x-1.
As S = D/T.

New speed of Abhay is calculated as -
2s = 30/x-1 -->[2]

Substitute the above 's' value of [1] in the '2s' value of [2]

2(30/x+2) = 30/x-1.
By solving, we get x=4 --> time taken by Sameer.

So, time taken by Abhay = x+2 = 4+2 = 6.
Now, speed of Abhay = 30/6 = 5kmph.

Thank you.
(2)


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