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:
[A].
20
[B].
80
[C].
100
[D].
200
Answer: Option B
Explanation:
Let the number of students in rooms A and B be x and y respectively.
I can't understand the sentence "then the number of students in A is double the number of students in B" explain me.
Mmmm said:
(Wed, Jul 27, 2011 03:27:03 PM)
Tell me clearly. Please.
Sundar said:
(Sat, Jul 30, 2011 03:48:23 PM)
Assume x,y
x-a, y-b
10 students from b-a. So x-b,then y+b
Now doubled
2(y-20) then both equation solved.
Prasu said:
(Mon, Sep 19, 2011 01:18:01 PM)
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.
Basheerbi said:
(Fri, Sep 23, 2011 05:12:35 PM)
I can't understand the prasu explanation tell me clearly.
Sandy said:
(Tue, Oct 4, 2011 03:16:27 PM)
Can you explain by assuming a = 100?
Raji said:
(Tue, Oct 11, 2011 08:15:19 PM)
Take these two cases individually let us look first through options 1st option is 20 so to apply both conditions is not possible so come to 80 so given if 10 people are sent to b then people in both class rooms are same so definetly b will be 60.
So again now apply second condition individually so by sending 20 people 4rm b A is twice that of B so this condition is not satisfied so now take 100 and check then both conditions satisfy and hence ans is 100
Raji said:
(Tue, Oct 11, 2011 08:18:00 PM)
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
x - y = 20 .... (i)
The required answer A = 100.