Aptitude - Pipes and Cistern - Discussion
Discussion Forum : Pipes and Cistern - General Questions (Q.No. 12)
12.
A large tanker can be filled by two pipes A and B in 60 minutes and 40 minutes respectively. How many minutes will it take to fill the tanker from empty state if B is used for half the time and A and B fill it together for the other half?
Answer: Option
Explanation:
| Part filled by (A + B) in 1 minute = |  |
1 | + | 1 |  |
= | 1 | . |
| 60 | 40 | 24 |
Suppose the tank is filled in x minutes.
| Then, | x | |
1 | + | 1 | |
= 1 |
| 2 | 24 | 40 |
 |
x | x | 1 | = 1 |
| 2 | 15 |
x = 30 min.
Discussion:
51 comments Page 2 of 6.
Siddhesh said:
8 years ago
(A+B) & B are not working simultaneously, one of them assume B first work for say x minutes and fill some part of tank.
According to question other (A+B) also work for x minute to fill the remaining part.
The part filled by B in x minutes = x/40,
part filled by (A+B) in x minutes.
= x/24
(x/40) + (x/24)=1
x =15
So total time is 2x = 30 min.
According to question other (A+B) also work for x minute to fill the remaining part.
The part filled by B in x minutes = x/40,
part filled by (A+B) in x minutes.
= x/24
(x/40) + (x/24)=1
x =15
So total time is 2x = 30 min.
(1)
Pankaj bansal said:
1 decade ago
Here,
B's 1 minute capacity is 1/40
A and B combined capacity is 1/24 to fill whole tank
Let x is total time
now x/2 X 1/40 { time for which B alone is works
and x/2 X 1/24 { time for which A and B both works
Now add both (as total time to flll the tank) and take common x/2
We get x/2(1/40 +1/24)=1 {1 is for full tank}
B's 1 minute capacity is 1/40
A and B combined capacity is 1/24 to fill whole tank
Let x is total time
now x/2 X 1/40 { time for which B alone is works
and x/2 X 1/24 { time for which A and B both works
Now add both (as total time to flll the tank) and take common x/2
We get x/2(1/40 +1/24)=1 {1 is for full tank}
Soham said:
7 years ago
The answer is wrong.
The question didn't ask, they did in halftime, the question asked they did the half work. So let's solve it simple way.
40 minty tea for full work for B, so 20 minutes for half work for B.
24 minutes for both AandB, so 12 minutes for half work for B.
SO TOTAL TIME TAKEN IS 20+12=32 minutes, 30 is wrong answer.
The question didn't ask, they did in halftime, the question asked they did the half work. So let's solve it simple way.
40 minty tea for full work for B, so 20 minutes for half work for B.
24 minutes for both AandB, so 12 minutes for half work for B.
SO TOTAL TIME TAKEN IS 20+12=32 minutes, 30 is wrong answer.
(1)
Bhushan said:
9 years ago
By LCM method answer is 32.
A B A+B
60 40 24 ---> Time.
2 3 5(3+2) ---> lit/min.
___ ___ _____
120 120 120 ---> capacity
For 60 lit, B will continue so it will take 20min.
And remaining 60 lit both A+B will work i.e will take 12min.
Total time = 20 + 12 = 32min.
A B A+B
60 40 24 ---> Time.
2 3 5(3+2) ---> lit/min.
___ ___ _____
120 120 120 ---> capacity
For 60 lit, B will continue so it will take 20min.
And remaining 60 lit both A+B will work i.e will take 12min.
Total time = 20 + 12 = 32min.
Rohit said:
8 years ago
LCM of 60 and 40 is 120.
So a 1 min work is 120/60=2.
And b 1 min work is 120/40=3.
After getting 1 min work by LCM as A=2 and b=3..consider full time as x so the halftime will be x/2.
So,
3x/2 + (2+3)x/2=120...solving it u get x=30.
Here 120 is taken on right because it's the total quantity.
So a 1 min work is 120/60=2.
And b 1 min work is 120/40=3.
After getting 1 min work by LCM as A=2 and b=3..consider full time as x so the halftime will be x/2.
So,
3x/2 + (2+3)x/2=120...solving it u get x=30.
Here 120 is taken on right because it's the total quantity.
(1)
Bhavadip Gothadiya said:
7 years ago
The answer May be 32.
LCM of 40 and 60 (240).
tank A one minutes ( 240/60)==4.
tank B one minutes (240/40)==6.
The half Filled by Tank B.
120/6 === 20 Minutes.
Half filled together.
120/10 === 12 minutes.
Here maybe 32 answer
anyone Explain to me please why not 32?
LCM of 40 and 60 (240).
tank A one minutes ( 240/60)==4.
tank B one minutes (240/40)==6.
The half Filled by Tank B.
120/6 === 20 Minutes.
Half filled together.
120/10 === 12 minutes.
Here maybe 32 answer
anyone Explain to me please why not 32?
(2)
Sri said:
1 decade ago
Please check the answer is 32 minutes,
B can fill a tank in 40 minutes means it can fill half tank by 20 minutes
Half tank B = 20 minutes.
A and B can fill a tank in 24 minutes means it can fill half tank by 12 minutes
Half tank A+B = 12 minutes
So, the answer is 32 minutes.
B can fill a tank in 40 minutes means it can fill half tank by 20 minutes
Half tank B = 20 minutes.
A and B can fill a tank in 24 minutes means it can fill half tank by 12 minutes
Half tank A+B = 12 minutes
So, the answer is 32 minutes.
Ishan said:
1 decade ago
We have to consider half time for both b and (a and b).
So if we consider time =x min then..for half time we have to take x/2 so we get x\2(1/40)wich is for b + x/2(1/24)wich is for both a and b.
So taking common we get x/2(1/40+1/24)=1 which 1 means to full whole tank.
So if we consider time =x min then..for half time we have to take x/2 so we get x\2(1/40)wich is for b + x/2(1/24)wich is for both a and b.
So taking common we get x/2(1/40+1/24)=1 which 1 means to full whole tank.
Sagar said:
9 years ago
1st tape can fill half of the tank in 3 hours.
Remaining part = 1-1/2 = 1/2 part.
Now 4 tape can fill the tank in 1 hour = 4*1/6 = 2/3.
Now,
2/3 parts fill in 1 hour.
1/2 parts fill in 1*3/2*2 = 45 mins.
So, total time = 3hrs+45mins = 3 hours 45 mins.
Remaining part = 1-1/2 = 1/2 part.
Now 4 tape can fill the tank in 1 hour = 4*1/6 = 2/3.
Now,
2/3 parts fill in 1 hour.
1/2 parts fill in 1*3/2*2 = 45 mins.
So, total time = 3hrs+45mins = 3 hours 45 mins.
Vinayak said:
10 years ago
L.C.M of 40 and 60 is 120.
So A's rate of work is 2 and B's rate of work is 3.
Hence now B work for half of time an A+B for another half.
So, 3x+(2x3)x = 120.
Hence x = 15 which is half time hence full time is 2x = 2x15 = 30 min.
So A's rate of work is 2 and B's rate of work is 3.
Hence now B work for half of time an A+B for another half.
So, 3x+(2x3)x = 120.
Hence x = 15 which is half time hence full time is 2x = 2x15 = 30 min.
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