# CAT Practice : Speed Time, Races

## Increasing Speed

Q.22: Akash when going slower by by 15 Km/hr, reaches late by 45 hours. If he goes faster by 10 Km/hr from his original speed, he reaches early by by 20 hours than the original time. Find the distance he covers.
1. 8750 Km
2. 9750 Km
3. 1000 Km
4. 3750 Km

Choice B. 9750 Km

## Detailed Solution

You may solve for D and S by writing the equations as:
$\frac{D}{s-15} - \frac{D}{s} = 45$

$\frac{D}{s} - \frac{D}{s+10} = 20$

You can solve these two equations to get D = 9750 Km which is a perfectly fine approach. However, if you are comfortable with alligation, you may save time on such TSD question as:

Both these equations can be solved quickly to get s = 65 Km/hr, t = 150 hr. Therefore, D = 9750 Km. I want to reiterate that using the first approach is perfectly fine. That's how I would do it. It is better to spend 20 seconds extra and get the right answer instead of getting it wrong with something you are not comfortable with.

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## More questions from Speed Time, Races

"Life is a race ... if you don't run fast ... you will be like a broken undaa" - Veerusahasra Buddhi