Advertisements
Advertisements
प्रश्न
A and B can do a piece of work in 18 days; B and C in 24 days and A and C in 36 days. In what time can they do it, all working together?
Advertisements
उत्तर
\[\text{ Time taken by } \left( A + B \right) \text{ to do the work = 18 days } \]
\[\text{ Time taken by } \left( B + C \right) \text{ to do the work = 24 days } \]
\[\text{ Time taken by } \left( A + C \right) \text{ to do the work = 36 days } \]
\[\text{ Now } , \]
\[\text{ Work done by } \left( A + B \right) = \frac{1}{18}\]
\[ \text{ Work done by } \left( B + C \right) = \frac{1}{24}\]
\[ \text{ Work done by } \left( A + C \right) = \frac{1}{36}\]
\[ \therefore \text{ Work done together } = \left( A + B \right) + \left( B + C \right) + \left( A + C \right)\]
\[ = \frac{1}{18} + \frac{1}{24} + \frac{1}{36}\]
\[ = \frac{4 + 3 + 2}{72} = \frac{9}{72}\]
\[ = \frac{1}{8}\]
\[ \therefore \text{ Work done together } = 2\left( A + B + C \right) = \frac{1}{8}\]
\[ \therefore \text{ Work done by } \left( A + B + C \right) = \frac{1}{16}\]
\[ \text{ Thus, together they can finish the work in 16 days } .\]
संबंधित प्रश्न
Fill in the blank in of the following so as to make the statement true:
If u = 3 v, then u and v vary .... with each other.
Complite the following table given that x varies directly as y .
| x | 3 | 5 | 7 | 9 |
| y | ... | 20 | 28 | ... |
Aasheesh can paint his doll in 20 minutes and his sister Chinki can do so in 25 minutes. They paint the doll together for five minutes. At this juncture they have a quarrel and Chinki withdraws from painting. In how many minutes will Aasheesh finish the painting of the remaining doll?
x and y are said to vary directly with each other if for some positive number k, ______ = k.
A car is travelling 48 km in one hour. The distance travelled by the car in 12 minutes is ______.
Write whether the following statement vary directly, vary inversely with each other, or neither of the two.
Number of students in a hostel and consumption of food.
If Naresh walks 250 steps to cover a distance of 200 metres, find the distance travelled in 350 steps.
From the following table, determine if x and y are in direct proportion or not.
| x | 3 | 6 | 15 | 20 | 30 |
| y | 12 | 24 | 45 | 60 | 120 |
The table shows the time four elevators take to travel various distances. Find which elevator is fastest and which is slowest.
| Distance (m) | Time (sec.) | |
| Elevator- A | 435 | 29 |
| Elevator- B | 448 | 28 |
| Elevator- C | 130 | 10 |
| Elevator- D | 85 | 5 |
How much distance will be travelled by elevators B and C separately in 140 sec? Who travelled more and by how much?
Here is a keyboard of a harmonium: What is the ratio of black keys to all keys on the given keyboard.
