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:
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 9 of 10.
Bhiksham Marepally said:
1 decade ago
Hi @Swathi, the answer for your question is 47.5 minutes.
How means,
For 5 minutes secret can be told to 2 people,
In the next 5 minutes 2 people can told to another 2 people each so total 4 in second 5 minutes.
3rd 5 minutes 8.
4th 5 minutes 16.
.........
.........
9th 5 minutes 512.
Now the completed minutes are 9*5=45 minutes and secret reached to 512 persons.
In the next 5 minutes it can reach to 1024 people but we don't have 1024 people, we have only 768 people..so the people who didn't get the secret till now are 256.
So within 2.5 minutes if the persons in (512/2) told secret to one person each, then the secret will be reaching to 768 people in 45+2.5 = 47.5 minutes.
How means,
For 5 minutes secret can be told to 2 people,
In the next 5 minutes 2 people can told to another 2 people each so total 4 in second 5 minutes.
3rd 5 minutes 8.
4th 5 minutes 16.
.........
.........
9th 5 minutes 512.
Now the completed minutes are 9*5=45 minutes and secret reached to 512 persons.
In the next 5 minutes it can reach to 1024 people but we don't have 1024 people, we have only 768 people..so the people who didn't get the secret till now are 256.
So within 2.5 minutes if the persons in (512/2) told secret to one person each, then the secret will be reaching to 768 people in 45+2.5 = 47.5 minutes.
Shazeab choudhary said:
1 decade ago
6250-5050 = 1200.
5200-1200 = 4000.
5200-1200 = 4000.
Ratnakar said:
2 decades ago
It can also done as (i) + (iii) - (ii).
Vishesh said:
1 decade ago
@Praveen how did you get -(q+r) can you explain in detail?
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.
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.
MIITAL said:
1 decade ago
p and Q = 5050.
Q and R = 6250.
P and R = 5200.
NOW TOTAL OF
P AND Q = 5050.
P AND R = 5200.
= 10250.
NOW(10250-6250) = 4000.
Q and R = 6250.
P and R = 5200.
NOW TOTAL OF
P AND Q = 5050.
P AND R = 5200.
= 10250.
NOW(10250-6250) = 4000.
Srikanth said:
1 decade ago
Why we do like:
5050*2 =
6250*2=
From where we get this 2 value.
Can you explain any one?
5050*2 =
6250*2=
From where we get this 2 value.
Can you explain any one?
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.
(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.
Srinivas said:
1 decade ago
p+q= 5050
p+r=5200
total= 10250
here substract(-)q+r = 6250
p = 4000 (ans)
p+r=5200
total= 10250
here substract(-)q+r = 6250
p = 4000 (ans)
Clarification said:
1 decade ago
@Praveen's process simple n right..but he forget multiply r.h.s with 2 because it is average of two items.
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