Aptitude - Simplification - Discussion
Discussion Forum : Simplification - General Questions (Q.No. 2)
2.
There are two examinations rooms A and B. If 10 students are sent from A to B, then the number of students in each room is the same. If 20 candidates are sent from B to A, then the number of students in A is double the number of students in B. The number of students in room A is:
Answer: Option
Explanation:
Let the number of students in rooms A and B be x and y respectively.
Then, x - 10 = y + 10 
x - y = 20 .... (i)
and x + 20 = 2(y - 20) x - 2y = -60 .... (ii)
Solving (i) and (ii) we get: x = 100 , y = 80.
The required answer A = 100.
Discussion:
75 comments Page 3 of 8.
Prashant said:
1 decade ago
It is very simple assume maximum capacity of seats in both room is 100, now A:B = 100:80.
There is no need to think about 1st equation or second just do maximum-lesser no. of side.
There is no need to think about 1st equation or second just do maximum-lesser no. of side.
Pari said:
1 decade ago
They said the number of students in A is double the number of students in B. We should multiply A by 2 instead of multiplying B by 2. Why we are multiplying A by 2? Please tell me.
Hiranmoy said:
8 years ago
X-10 = y+10.
X-y = 10+10.
=20 (i).
Then, x+20 = 2(y-20)
x-2y = 40
x-y = 2x40
x-y = 80 (ii).
Now adding (i) &(ii) we get 20+80 = 100.
X-y = 10+10.
=20 (i).
Then, x+20 = 2(y-20)
x-2y = 40
x-y = 2x40
x-y = 80 (ii).
Now adding (i) &(ii) we get 20+80 = 100.
Prasu said:
1 decade ago
Based on the answer a=100 and b=80. They said that if 20 sent from a to b then.
A will become double of b.
So if 20 sent then a=120 and b=60 i.e. a is double of b.
A will become double of b.
So if 20 sent then a=120 and b=60 i.e. a is double of b.
Nandhakumar said:
1 decade ago
Then the number of students in A is double the number of students in B" so the step was look like 2(x+20) = (y-20). Then how it come(x+20) = 2(y-20).
Devicky said:
1 decade ago
In this a to b represents the equation x-10 = y+10.
In this b to a represents the equation x+20 = 2(y-20).
Solving 2 equation we get the answer.
In this b to a represents the equation x+20 = 2(y-20).
Solving 2 equation we get the answer.
Alpesh Patel said:
5 years ago
x-y=20
x=20+y ---> (1)
x-2y=-60 ---> (2)
20+y-2y=-60 --->(3)
+y-2y=-60-20
-y=-80
y=80
Sub value of y in eqn 1, we get;
x=20+80 = 100.
x=20+y ---> (1)
x-2y=-60 ---> (2)
20+y-2y=-60 --->(3)
+y-2y=-60-20
-y=-80
y=80
Sub value of y in eqn 1, we get;
x=20+80 = 100.
(11)
Raji said:
1 decade ago
Its simple given second condition that by sending 20 people A is twice of B so A+20=2(B-20) and solving both conditions we get 100
Srividya said:
9 years ago
Friends as the question had given that A is doubled then why we doubled B? Can anyone explain this problem in another process?
Akilapriya said:
1 decade ago
I can't understand the sentence "then the number of students in A is double the number of students in B" explain me.
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