Given below are two quantities named I and II. Based on the given information, you have to determine the relation between the two quantities. You should use the given data and your knowledge of Mathematics to choose among the possible answers. Quantity I: A alone can do a piece of work in 30 days. If A and B can do the same piece of work in 20 days, then B alone can do the same piece of work in how many days? Quantity II: Two pipes M and N can fill a tank in 15 hours and 20 hours respectively. These pipes are opened alternately and pipes M is opened first, in how many hours, the tank fill-in?
Given below are two quantities named I and II. Based on the given information, you have to determine the relation between the two quantities. You should use the given data and your knowledge of Mathematics to choose among the possible answers. Quantity I: A alone can do a piece of work in 30 days. If A and B can do the same piece of work in 20 days, then B alone can do the same piece of work in how many days? Quantity II: Two pipes M and N can fill a tank in 15 hours and 20 hours respectively. These pipes are opened alternately and pipes M is opened first, in how many hours, the tank fill-in? Correct Answer Quantity I > Quantity II
Given:
A can do a piece of work in = 30 days
A and B can do the same piece of work in = 20 days
Concept used:
1/A + 1/B = 1/A + B
Calculation:
Let time taken by B alone be x days
A’s one day work = 1/30
B’s one day work = 1/x
(A + B)’s one day work = 1/20
Now,
1/30 + 1/x = 1/20
⇒ 1/x = 1/20 – 1/30
⇒ 1/x = (3 – 2)/60
⇒ 1/x = 1/60
⇒1/x = 1/60
⇒ x = 60
∴ The Time is taken by B alone will be 60 days
Quantity II:
Given:
Time taken by pipe M = 15 hours
Time taken by pipe N = 20 hours
Calculation:
Let the total capacity of tank be LCM (15, 20) = 60 litres
Now,
Tank filled by M in 1 hour = 60/15
⇒ 4 litre/hour
Tank filled by N in 1 hour = 60/20
⇒ 3 litre/hour
Tank filled by (M + N) in 1 hour = (4 + 3)
⇒ 7 litre/hour
Now,
According to the question,
For first hour pipe M is opened = 4 litre
For second hour pipe N is opened = 3 litre
For third hour pipe M is opened = 4 litre
For fourth hour pipe N is opened = 3 litre
Similarly, So…. On
Now,
We conclude that –
2 hours = 7 litre
× 8 × 8
16 hours = 56 litre
Now,
The remaining work = 60 – 56
⇒ 4 litre
Now,
Again 17th hour M will be opened and fill the remaining tank
⇒ 4/4
⇒ 1 hour
Now,
The tank fills in = (16hour + 1 hour)
⇒ 17 hours
∴ The tank will be fill in 17 hours.
The comparison of both the Result:
∴ Quantity I > Quantity II