Aptitude - Time and Distance - Discussion

Let suppose car speed = x km/h

As per problem train speed 50% more than car so = x+50/100x = 3/2x.

For people who still has confusion with the 150*x/100:

Why don't you remember the LCM formula?.. if speed of car is x then speed of train is more than speed of car by 50% of it. so after we calculate 50% of speed of car, we should not forget to add the result of it to the actual speed of car, i.e-
[50% of x]+x
= [(50/100)*x]+x
= [50x/100]+x... now, this is actually [50x/100]+[x/1] the two denominators '100' and '1' here are 100, and 1 and the LCM of the two is 100. This makes 100 the common denominator. now following the rule of LCM, divide the common denominator by the first actual denominator, i.e 100/100, the result is '1', and now multiply the first numerator by this result '1' that keeps 50x*1 that is the same, so basically the first numerator does not change. now, do the same with the second denominator, multiply this common denominator 100 by the second actual denominator, i.e 100/1, the result is '100', and now multiply the second numerator by this result '100' that makes it 100*x that is 100x.. so after the LCM now it looks like:
(50x+100x)/100.

Now take x as common and comprehend this numerator as-
x(50+100)/100
=x(150)/100
=150x/100
DID U GET THIS NOW? THE TRICK LIES IN THE LCM FORMULA !!

This can again be derived to 3x/2, applying the ratio formula.

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Here is another simpler method.. when we calculate speed of train as 50% more than that of the car, in a lay-man's language it simply means speed of train is more than speed of car by half of car's speed, so instead of 50% of car's speed, we can also do half of car's speed, and if car's speed is 'x', then train's speed is

(x/2)+x, applying the same LCM formula, take 2 as the common denominator and the first numerator remains 'x' and the second numerator becomes '2*x'
= (x+2x)/2, now if u remember, 'x' is equivalent to '1*x', as per basic algebra logic- so,
= 3x/2.

GOT THE SAME ANSWER ??

How we get 125/10*60?

Can any one explain easy way?

A is faster than B by 50 percent means, take a is 100 percent and more 20 percent faster than 100+20=120. And take B is 100 percent. Then 150/100.

Why 10 is multiplied with 12.5? Can anybody explain?

Here,in this problem if we take 50/100 then it becomes 1/2

So we have to take 50% more..

So,assuming car speed is 100 %,then increase it to 50%..means 100+50/100 = 150/100

In given problem ,u ve to equate total or exact time of both...

Let t be time tkn by car to cover 75kms... n t' be time takn by train...

i.e. train's total time=stoppage time+time in which it covers 75kms...nw t=t'....

First we assume that the speed of car is 100% so as per Q.speed of train is 150%.

Sarvya Kanchna is right:-)

dont consider x with 100 consider with 50 like this.
=x+50x/100
=(100x+50x)/100
=150x/100

If you consider x with 100 then when we take LCM then eq.
=(100x^2+50)/100x
:-)

@kanchana

How did x+50/100 became 100x+50x as it will become (100x+50)/100x ?