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:
76 comments Page 4 of 8.
Sagar said:
7 years ago
Thanks @Naga invy.
Geethanjali said:
8 years ago
Simple to understand Thank you @Hiranmoy.
Garry said:
8 years ago
Accroding to last condtion, It should be 2(x+20).
Nagesh v said:
7 years ago
Thank for you answer @Ash.
Kaleem said:
7 years ago
Thank you all.
Saurya said:
7 years ago
Thank all for explaining.
Prakash said:
6 years ago
Could you please explain this? I am not getting it.
Koteswararao chimmili said:
9 years ago
If 10 students are sent from A to B,then the number of students in each room is the same
a-10 = b+10 ; ---- (1)
If 20 candidates are sent from B to A, then the number of students in A is double the number of students in B.
a+20 = 2(b -20); ---- (2) ( suppose A=10,B=5 that means A=2B then 10=10 )
Equation 1
a-10 = b+10.
a-b = 20.
Equation 2
a+20 = 2(b-20)
a+20 = 2b -40
a-2b = -60.
Solving equation 1 and 2
a-b = 20
a-2b = -60 (-a+2b = +60)
_____________.
b = 80
b is substitute in equation 1
a - b = 20
a = 20 + b
a = 20 + 80
a = 100
The answer is a = 100
a-10 = b+10 ; ---- (1)
If 20 candidates are sent from B to A, then the number of students in A is double the number of students in B.
a+20 = 2(b -20); ---- (2) ( suppose A=10,B=5 that means A=2B then 10=10 )
Equation 1
a-10 = b+10.
a-b = 20.
Equation 2
a+20 = 2(b-20)
a+20 = 2b -40
a-2b = -60.
Solving equation 1 and 2
a-b = 20
a-2b = -60 (-a+2b = +60)
_____________.
b = 80
b is substitute in equation 1
a - b = 20
a = 20 + b
a = 20 + 80
a = 100
The answer is a = 100
Prakash said:
6 years ago
Could you please explain this? I am not getting it.
Geetha said:
7 years ago
Please Explain the 2nd step.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers