Aptitude - Time and Distance - Discussion

Thank you so much for everyone, who are all posted the method of hour conversion. :).

Thanks @Siddharth.

Hello, They have given that speeds ratio 7 : 5 ie, 7x, 5x.

Hence second time speed gave ie,, 42/126/75 = 42 * 75/126 = 25.

5x = 25.
x = 5.
7x = 35.

Thank you, I hope you all understand.

Easiest Method:.

Speed = dis/time.
Let speed = x.

5/7(x) = 42/(126/75) = 35.

Hello here speed equals to distance by time.

Then 5x/7 = 42/126/75
It form as, 5x/7 * 75/126 = 42

But solution is above mentioned is not matched with my answer. Anyone explain it please.

Thanks

@Kasaiah.

Please see above discussions, there is already so many threads of same question. They have explain it very simple manner. Follow one you find easy and quick. :)

1 hr 40 min 48 sec lets assume 48 sec as one minute then total 1 hr 41 min that means 101 min now convert 101 min to hr = 101/60 = 1.683. This is just for those who find it difficult to convert.

1st convert 48 sec to min. 48/60 = 0.8 again convert 0.8 min to hr 0.8/60 = 0.0133 i.e 48sec = 0.0133 hr.
Now convert 40 min to hr 40/60 = 0.6666,
40 min = 0.666 hr,
Now 1 hr 40 min 48 sec = 1 + 0.666 + 0.01333 = 1.6793 = 1.68 hr,

Given:
Speed = 5/7 of its actuall speed = 0.71428 of its actual speed,
Distance D = 42 km,
Time T = 1.68 hr,

Formula S = D/T,
0.71428 * actuall speed = 42/1.68,
0.71428 * actuall speed = 25,
Actuall speed = 25/0.71428,
Actuall speed = 35 km/hr.

Why we multiply by 5/7?

Because Actual speed is X and actual speed 5/7 so X. 5/7.

Speed * time = distance.

Let assume Actual speed be = x,
Distance = 42,
Time = 1 + (40÷60) + (48÷ 3600) = 1.68,
Hence 5x/7* 1.68 = 42,
5x/7 = 42/1.68,
5x/7 = 25,
5x = 25 * 7,
5x = 175,
X = 175/5,
And X = 35.