Aptitude - Average - Discussion

Discussion Forum : Average - General Questions (Q.No. 7)
7.
The average monthly income of P and Q is Rs. 5050. The average monthly income of Q and R is Rs. 6250 and the average monthly income of P and R is Rs. 5200. The monthly income of P is:
3500
4000
4050
5000
Answer: Option
Explanation:

Let P, Q and R represent their respective monthly incomes. Then, we have:

P + Q = (5050 x 2) = 10100 .... (i)

Q + R = (6250 x 2) = 12500 .... (ii)

P + R = (5200 x 2) = 10400 .... (iii)

Adding (i), (ii) and (iii), we get:  2(P + Q + R) = 33000  or   P + Q + R = 16500 .... (iv)

Subtracting (ii) from (iv), we get P = 4000.

P's monthly income = Rs. 4000.

Discussion:
93 comments Page 4 of 10.

Rahul said:   1 decade ago
(p+q)/2 = 5050...(1)
(q+r)/2 = 6250...(2)
(p+r)/2 = 5200...(3)

From (1) and (2)

q=10100-p
r = 12500-q
Sub in (3)

p=10400-r
=10400-12500+q
=10400-12500+10100-p
p=(10400-12500+10100)/2=4000.

B.E(Bekar Engg) said:   1 decade ago
(p+q) + (q+r) + (p+r) here p, q, r comes two time;

So that, 2(p+q+r) =16500.

16500/2 = 8250;

p+q+r = 8250;

q+r = 6250;

8250-6250 = 2000;

As above mention p is 2 time. So 2(2000) = 4000;

Shiva said:   1 decade ago
P + Q = (5050 x 2) = 10100
Q + R = (6250 x 2) = 12500
P + R = (5200 x 2) = 10400

add above three

2(p+q+r)=33000
(p+q+r)=16500

we need 'p' only so

(p+q+r)-(q+r)=16500-12500

so p=4000...

Bhanu ravali said:   1 decade ago
P + Q + = 10100.

+ Q + R = 12500.

---------------

P + 2Q + R = 22600.

P + + R = 10400 (subtraction).

--------------

2Q = 12200.

Q = 6100.

P + Q = 10100.

P = 10100 - 6100.

= 4000.

Anjaneyulu said:   5 years ago
In question, he said an average of p and q =5050
Average means the sum of items by a number of items.

Here items are p and q so they are 2 .so the average is p+q/2=5050, dr4 p+q=1100.
(2)

Samar said:   1 decade ago
p+q=5050
q+r=6250
p+r=5200
p+q+q+r+p+r=5050+6250+5200
2(p+q+r)=16500
p+q+r=16500/2
=8250
p+6250+8250
p=8250-6250
p=2000(Ans

A get the 2000Ans
How it comes 4000?

Please help me.

Sana. said:   1 decade ago
Adding (i), (ii) and (iii), we get: 2(P + Q + R) = 33000 or P + Q + R = 16500 .... (iv)

Subtracting (ii) from (iv), we get P = 4000.

So why did we subtract from (ii) ?

Asmara said:   9 years ago
Why we subtract total from equation (ii) as that is a monthly income of Q+R. How we can assume it's P's monthly income while there is No written P, Please explain.

MAHESH said:   1 decade ago
p+q = 10100
p+r = 10400
q+r = 12500

q+r = 12500
p+r = 10400(-)
---------------
q-p = 2100

p+q = 10100
-p+q = 2100 (-)
-------------
2p = 8000

p = 4000.

Dora said:   7 years ago
Add the values of ( PQ+PR) - QR ie;

By doing this the value of Q and R will be excluded from both PQ and PR.
= (5050+5200)-6250,
=10200-6250.
= 4000.


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