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 8 of 10.

K L N Sarma said:   7 years ago
Guys, if you say p=4000, what will be your answers for Q and R.

My answer is p=2000, Q=3050, R = 3200
If we add all the 3 equations, we get 2 times (P+Q+R) = 16500. therefore, P+Q+R = 16500/2 = 8250.
8250 - (Q+R) = 8250-6250 = 2000.

Bhanu said:   7 years ago
Thank you @Prabhjeet.

Akhilesh said:   7 years ago
Thanks for the @Sai Kumar.

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.

Kiran said:   7 years ago
Well said @Dora.

Raghavendra said:   7 years ago
@Praveen.

The initial step wrong.

P+q=5050.
Q+r=6250.
P+r=5200.
Each value should multiply with 2 as it was average, not individual.

Shahrukh said:   7 years ago
I don't know why the amount of q and are is being deducted?

P has two incomes 5050 and 5200. Why are the incomes of q and r is concerned with p? As it is cleared that p has these incomes. Question is about the income of p not about q and r.

Deepak Kumar sharma said:   6 years ago
5050 + 5200 = 10250-6250 = 4000.

Dibyansh Pattanaik said:   6 years ago
@All.

1. Why we subtracted QR or Why we deducted QR?
2. What would be the solution if the monthly income of Q is asked?

Please, anyone, clarify it.

Sakshi Pandey said:   6 years ago
P + q= 5050*2=10100.
Q+r= 6250*2=12500.
P+r= 5200*4= 10400.

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


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