Aptitude - Average - Discussion

Average income of P & Q is 5050.
This means, P's average is 5050 & Q's average is 5050.
now, we can write P+Q => 5050 + 5050 = 10100 ----> 1

Similarly for Q and R average salary is 6250
hence, Q + R => 6250 + 6250 = 12500 ---> 2

Similarly for P and R average salary is 5200
hence, P + R => 5200 + 5200 = 10400 ---> 3

Adding all these equations, we get:
(P+Q)+(Q+R)+(P+R) => 10100+12500+10400 = 33000,
(P+Q)+(Q+R)+(P+R) can be written as 2(P+Q+R).

Hence, 2(P+Q+R) = 33000,
P + Q + R = 33000/2 = 16500.

we want P so:
P = 16500 - (Q+R),
P = 16500 - 12500 ( from 2),
P = 4000.

Work done by p,q is 5050.
Work done by q,r is 6250.


So,
6250 - 5050 = 1200,
ie 5200 - 1200=4000
Which is work done by P.

In simple word;
5050 + 5200 = 10250.
10250 - 6250 = 4000.

The correct answer is 4000.

No confusion we can do like this,

P + Q = (5050 x 2) = 10100,
Q + R = (6250 x 2) = 12500,
P + R = (5200 x 2) = 10400.

We need only p so,

p+q-(q+r)+p+r = p+q-q-r+p+r= 2P(cancel r and q).

10100 - 12500 + 10400 = 8000.
2P = 8000.
P = 4000.
That's it.

No confusion we can do like this,

P + Q = (5050 x 2) = 10100,
Q + R = (6250 x 2) = 12500,
P + R = (5200 x 2) = 10400.

We need only p so,

p+q-(q+r)+p+r = p+q-q-r+p+r= 2P(cancel r and q).

10100 - 12500 + 10400 = 8000.
2P = 8000.
P = 4000.
That's it.

p+q = 10100.
q+r = 12500.
p+r = 10400.

So we can say (p+q)+(q+r)+(p+r) = 10100 + 12500 + 10400.
we can write this as 2(p+q+R)= 33000,
p+q+r = 16500.

Now q+r= we know (12500),
p+12500= 16500,
p= 16500-12500,
Hence p= 4000.

SIMPLE;

(p+q)/2 = 5050 ------> (1)
(q+r)/2 = 6250 ------> (2)
(p+r)/2 = 5200 ------> (3)
(2) - (1) ------> r= p + 2400.
Substitude r in (3)
(p + p + 2400)/2 = 5020.
2p = 10400 - 2400.
2p =8000.
p = 4000.

In simple words, 5050 + 5200 = 10250.

10250 - 6250 = 4000.

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.

P&Q+P&R=5050+5200=10250.

Q&R=10250 (PQR total value) -6250 (QR) =4000 this is answer.