Quantitative Aptitude – TSD – Vimla starts for office every day at 9 am

Slot – 3 – Quantitative Aptitude – TSD – Vimla starts for office every day at 9 am

Q. Vimla starts for office every day at 9 am and reaches exactly on time if she drives at her usual speed of 40 km/hr. She is late by 6 minutes if she drives at 35 km/hr. One day, she covers two-thirds of her distance to office in one-thirds of her usual time to reach office, and then stops for 8 minutes. The speed, in km/hr, at which she should drive the remaining distance to reach office exactly on time is?

1. 27
2. 26
3. 29
4. 28

Answer: 28

Solution:
Let the time taken with its usual speed = x
So distance that she covers = 40x
Now 40x = 35*(x + 6/60) = 35x + 3.5
5x = 3.5
Or x = 0.7 hrs = 42 min
So distance = 40x = 40*0.7 = 28 km
As per question, she covers 2/3 rd of distance in 1/3rd time that is 56/3 km in 42/3 = 14 min
She took rest for 8 min so total time remains = 42 – 8 – 14 = 20 min
And she need to cover = 28 – 56/3 = 28/3 km
So required speed = (28/3)/(20/60) = 28 kmph

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