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 2 of 8.
Syed Taher zama said:
1 decade ago
To solve equations:
(A part) (B part)
x + 20 = 2(y - 20)
20 candidates are sent from B to A,so we are adding 20 to x,and because we are sending 20 students to A it gets doubled(A=2B).
And
For solving equations just subtract both.
x - y = 20 .... (i)
x - 2y = -60 .... (ii)
You will get y=80 and then substitute in eq(i) you will get x=100.
(A part) (B part)
x + 20 = 2(y - 20)
20 candidates are sent from B to A,so we are adding 20 to x,and because we are sending 20 students to A it gets doubled(A=2B).
And
For solving equations just subtract both.
x - y = 20 .... (i)
x - 2y = -60 .... (ii)
You will get y=80 and then substitute in eq(i) you will get x=100.
Anup said:
1 decade ago
Everyone is going directly from solve equation 1&2,
x-y = 20.
x-2y = -60.
And result is y = 80 and x = 100.
No one explain how to solve this. What is the best formula to solve this. If you have no idea how to solve those equation don't write the same word again and again in comments here.
x-y = 20.
x-2y = -60.
And result is y = 80 and x = 100.
No one explain how to solve this. What is the best formula to solve this. If you have no idea how to solve those equation don't write the same word again and again in comments here.
Geetha said:
8 years ago
Assume A= 70 and B= 50.
Then according to question 10 students from A will be transferred to B so now they are going to b equal.
A=60 and B=60,
And if we transfer 20 students from B to A,
It's going to be A=80 and B=40 I.e A is double of B,
So why can't D answer be 80.
Then according to question 10 students from A will be transferred to B so now they are going to b equal.
A=60 and B=60,
And if we transfer 20 students from B to A,
It's going to be A=80 and B=40 I.e A is double of B,
So why can't D answer be 80.
Nonsocial said:
1 year ago
The students first sent from room A to B means 10 students sent from A to B so the number is equal between them just multiply;
i.e 10 × 10 = 100.
Then it's said from B to A they sent 20 students and A got double that B.
i.e 100 - 20 = 80.
i.e 10 × 10 = 100.
Then it's said from B to A they sent 20 students and A got double that B.
i.e 100 - 20 = 80.
(13)
Chandrasekhar said:
9 years ago
Students sent from A to B = 10;
Then A-10 = B+10; ---- (i)
Students sent from b to a = 20; then,
B-20 = A+20; --- (ii).
A is double no.of students in B so,
2(B-20) = A+20.
Solve 1 & 2, we get,
A = 100.
Then A-10 = B+10; ---- (i)
Students sent from b to a = 20; then,
B-20 = A+20; --- (ii).
A is double no.of students in B so,
2(B-20) = A+20.
Solve 1 & 2, we get,
A = 100.
(1)
Sreeram said:
8 years ago
See guys first take. x+10=2(y-40).
Then it comes as x-2y=-60,
First eq is x-y=20,
Solve both.
X-y=20,
x-2y=-60,
Change signs/
We get;
x-y=20,
-x+2y=60,
Then we get y=80,
Substitute in eq 1,
We get x=100.
Then it comes as x-2y=-60,
First eq is x-y=20,
Solve both.
X-y=20,
x-2y=-60,
Change signs/
We get;
x-y=20,
-x+2y=60,
Then we get y=80,
Substitute in eq 1,
We get x=100.
Chandu said:
6 years ago
We have to only subtract 10 students from A ie;A-10=B (OR) A=B+10.
But how do you add 10 to A sub 10 from B at a time that means 20 students are sending to B from A.
A-10=B,
B-20=2B=>B=20,
A-10=20,
A=30.
But how do you add 10 to A sub 10 from B at a time that means 20 students are sending to B from A.
A-10=B,
B-20=2B=>B=20,
A-10=20,
A=30.
(1)
Rajesh said:
8 years ago
We can find out the answer by option if the 1st option is 80. Consider the student of class B and transfer 10 students then in both the class are equal so definitely, A class has a 100 student then tally it.
Sumeet Kumar said:
1 decade ago
Amigos..
Then the number of students in A is double the number of students in B.
Just use is equal to "=" instead of "is" After A and then think of it.
Easy isn't it.
Then the number of students in A is double the number of students in B.
Just use is equal to "=" instead of "is" After A and then think of it.
Easy isn't it.
Shanthini said:
8 years ago
Friends I'll say one simple logic. If "is " is given after A then you must consider as A =. So as per question if we see means A is double the number of students in b.
So (x+20) =2 (y-20).
So (x+20) =2 (y-20).
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