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:
Answer: Option
Explanation:
Let Abhay's speed be x km/hr.
| Then, | 30 | - | 30 | = 3 |
| x | 2x |
6x = 30
x = 5 km/hr.
Discussion:
209 comments Page 18 of 21.
Vinay said:
7 years ago
Very good explanation, Thanks @Devi.
Apoorv said:
7 years ago
(30/x)-(30/2x)=3.
In 1st case LCM is x and in 2nd case LCM is 2x.now make both LCM equal.
(2*(30/x))-30/2x=3,
(60/2x)-(30/2x)=3,
(60-30)/2x=3,
(30/2x)=3,
30= 3*2x,
30=6x,
30/6=x,
5=x.
Note- multiply by whole fraction (2*(30/x) and by only x.
In 1st case LCM is x and in 2nd case LCM is 2x.now make both LCM equal.
(2*(30/x))-30/2x=3,
(60/2x)-(30/2x)=3,
(60-30)/2x=3,
(30/2x)=3,
30= 3*2x,
30=6x,
30/6=x,
5=x.
Note- multiply by whole fraction (2*(30/x) and by only x.
Yamini Dhanasekar said:
7 years ago
We can also solve it by finding a time,
Let, Abhay's speed-x, the time taken by Sameer-t.
X=30/t+2 --> (1)
When speed doubles
2X= 30/t-1..,
X=15/t-1 --> (2).
Equating (1) &(2)
30/t+2 = 15/t-1.
t=4.
Sub in eqn (1),
X = 30/4+2,
X = 5 kmph.
Let, Abhay's speed-x, the time taken by Sameer-t.
X=30/t+2 --> (1)
When speed doubles
2X= 30/t-1..,
X=15/t-1 --> (2).
Equating (1) &(2)
30/t+2 = 15/t-1.
t=4.
Sub in eqn (1),
X = 30/4+2,
X = 5 kmph.
Kiran shetty said:
7 years ago
Thank you so much @Devi.
Jafar said:
7 years ago
Given that Abhay+2 hours= Sameer.
And 2Abhy-1=Sameer.
On solving these two equations;
We will get Abhy = 3.
And Sameer = 5.
We need to find the Abhay speed that's why we take 3.
And 2Abhy-1=Sameer.
On solving these two equations;
We will get Abhy = 3.
And Sameer = 5.
We need to find the Abhay speed that's why we take 3.
Paparao said:
7 years ago
Thanks for your answer @Devi.
Kanisetty Ashok said:
7 years ago
Abhay's difference in covering the distance after doubling the speed is 2+1 = 3 hrs.
So, Abhay's speed after doubling the speed is 30/3 = 10,
So, the current speed of Abhay is 10/2 = 5.
So, Abhay's speed after doubling the speed is 30/3 = 10,
So, the current speed of Abhay is 10/2 = 5.
Avigeh said:
7 years ago
Suppose Abhay's speed is -x km/h.
then suppose y is Abhays speed;
(y+2)-(y-1)=3.
30/x-30/2x=3.
(60x-30x)/2x=3.
Ans is 5km/h.
then suppose y is Abhays speed;
(y+2)-(y-1)=3.
30/x-30/2x=3.
(60x-30x)/2x=3.
Ans is 5km/h.
Ameer said:
7 years ago
Abay = 2hour + Sameer, [you can analyze this equation by taking sameer=5, which gives Abay=7]
And; 2 * Abay = Sameer - 1, [similarly in this equation, suppose sameer=5, which results in Abay=4]
Both the equation satisfies the above statement.
And; 2 * Abay = Sameer - 1, [similarly in this equation, suppose sameer=5, which results in Abay=4]
Both the equation satisfies the above statement.
Arshid Ali said:
6 years ago
Thanks everyone for explaining.
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