Aptitude - Average - Discussion
Discussion Forum : Average - General Questions (Q.No. 11)
11.
The average weight of A, B and C is 45 kg. If the average weight of A and B be 40 kg and that of B and C be 43 kg, then the weight of B is:
Answer: Option
Explanation:
Let A, B, C represent their respective weights. Then, we have:
A + B + C = (45 x 3) = 135 .... (i)
A + B = (40 x 2) = 80 .... (ii)
B + C = (43 x 2) = 86 ....(iii)
Adding (ii) and (iii), we get: A + 2B + C = 166 .... (iv)
Subtracting (i) from (iv), we get : B = 31.
B's weight = 31 kg.
Discussion:
40 comments Page 2 of 4.
Prabakaran said:
9 years ago
a + b + c/3 = 45.
a + b + c = 135------>1.
We know b + c = 86.
substitute in eqn 1.
We get a + 86 = 135.
a = 49.
a + b/2 = 40.
49 + b = 80.
b = 31 //. Answer.
a + b + c = 135------>1.
We know b + c = 86.
substitute in eqn 1.
We get a + 86 = 135.
a = 49.
a + b/2 = 40.
49 + b = 80.
b = 31 //. Answer.
Priyanka said:
1 decade ago
A+B+C = 135---- (1).
A+B = 80---- (2).
B+C = 86---- (3).
Substitute (3) in (1).
A+86 = 135.
A = 49.
Substitute A in (2).
49+B = 80.
B = 80-49.
B = 31.
A+B = 80---- (2).
B+C = 86---- (3).
Substitute (3) in (1).
A+86 = 135.
A = 49.
Substitute A in (2).
49+B = 80.
B = 80-49.
B = 31.
Dora said:
7 years ago
ABC is (45*3)=135,
AB is (40*2)=80,
BC is (43*2)=86.
Now;
A+B+C=135,
'-----' +C=135,
80+C=135,
C=135-80,
C=55.
So,B+C=86.
B+55=86.
B=31.
AB is (40*2)=80,
BC is (43*2)=86.
Now;
A+B+C=135,
'-----' +C=135,
80+C=135,
C=135-80,
C=55.
So,B+C=86.
B+55=86.
B=31.
(8)
Ankur said:
1 decade ago
Simplified.
Sum of weights = 45*3 = 135.
A+B+C = (45*3).
A+B = (40*2)----1.
B+C = (43*2)----2.
From 1, 80+C=135 => c=55.
from 2, B+55=86=> B=31.
Sum of weights = 45*3 = 135.
A+B+C = (45*3).
A+B = (40*2)----1.
B+C = (43*2)----2.
From 1, 80+C=135 => c=55.
from 2, B+55=86=> B=31.
Drukyul said:
8 years ago
A+B+C=135.......(1)
B+C=86..............(2)
A+B=80..............(3)
A+86=135.
A=49....................(4)
Sub equ 4 in 3.
49+B=80,
B=80-49,
B=31.
B+C=86..............(2)
A+B=80..............(3)
A+86=135.
A=49....................(4)
Sub equ 4 in 3.
49+B=80,
B=80-49,
B=31.
(2)
ALIYAZ said:
1 decade ago
A+B+C = 45*3.
A+B = 80.
B+C = 86.
We want 'B', So A+B+C-(A+B)-(B+C).
=> A+B+C-A-B-B-C = 135-80-86.
=> -B = -31.
=> B = 31.
A+B = 80.
B+C = 86.
We want 'B', So A+B+C-(A+B)-(B+C).
=> A+B+C-A-B-B-C = 135-80-86.
=> -B = -31.
=> B = 31.
Dharshni said:
1 year ago
A + b + c = 45 * 3 = 135
A + b = 40 * 2 = 80.
B + c = 43 * 2 = 86.
Now.
(A+b)(b+c) = 80 + 86.
= 166.
166 - 135.
= 31kg.
A + b = 40 * 2 = 80.
B + c = 43 * 2 = 86.
Now.
(A+b)(b+c) = 80 + 86.
= 166.
166 - 135.
= 31kg.
(12)
Medha said:
8 years ago
B + c = 86 ( 1)
A + B + C = 135 (2)
A + B = 80 (3)
Substituting (1) in (2)
A = 135 - 86 = 49.
From (3):
B = 80 - 49 = 31.
A + B + C = 135 (2)
A + B = 80 (3)
Substituting (1) in (2)
A = 135 - 86 = 49.
From (3):
B = 80 - 49 = 31.
Jay Jadhao said:
1 decade ago
No * Avg = Sum.
3 * 45 = 135.
2(A,B)* 40 = 80.
2(B,C)* 43 = 86.
B= 86 - (135 - 80)= 31.
3 * 45 = 135.
2(A,B)* 40 = 80.
2(B,C)* 43 = 86.
B= 86 - (135 - 80)= 31.
Kaustubh l said:
1 decade ago
A+B+C = 45*3 = 135---(1).
A+B = 80.
Hence (1) becomes:
80+C = 135.
C = 55.
B+C = 43*2 = 86.
B = 86-55 = 31.
A+B = 80.
Hence (1) becomes:
80+C = 135.
C = 55.
B+C = 43*2 = 86.
B = 86-55 = 31.
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