Advertisements
Advertisements
प्रश्न
It takes 60 days for 10 machines to dig a hole. Assuming that all machines work at the same speed, how long will it take 30 machines to dig the same hole?
Advertisements
उत्तर
Let the number of days required be x.
| Number of machines | 10 | 30 |
| Number of days | 60 | x |
As the number of machines increases it takes less days to complete the work
∴ They are in inverse proportion, x1y1 = x2y2
10 × 60 = 30 × x
x = `(10 xx 60)/30`, x = 20
It takes 20 days to dig the hole
APPEARS IN
संबंधित प्रश्न
A farmer has enough food to feed 20 animals in his cattle for 6 days. How long would the food last if there were 10 more animals in his cattle?
Find the constant of variation from the table given below:
| x | 3 | 5 | 7 | 9 |
| y | 12 | 20 | 28 | 36 |
Set up a table and solve the following problems. Use unitary method to verify the answer.
A work-force of 420 men with a contractor can finish a certain piece of work in 9 months. How many extra men must he employ to complete the job in 7 months?
Mary cycles at 6 km per hour. How long will she take to reach her Aunt’s house which is 12 km away? If she cycles at a speed of 4 km/hr, how long would she take?
Neelaveni goes by bicycle to her school every day. Her average speed is 12 km/hr and she reaches school in 20 minutes. What is the increase in speed, If she reaches the school in 15 minutes?
In a school there is 7 periods a day each of 45 minutes duration. How long each period is if the school has 9 periods a day assuming the number of hours to be the same?
Which quantities in the previous question vary inversely with each other?
If 12 pumps can empty a reservoir in 20 hours, then time required by 45 such pumps to empty the same reservoir is ______ hours.
If d varies directly as t2, then we can write dt2 = k, where k is some constant.
If a and b vary inversely to other, then find the values of p, q, r ; x, y, z and l, m, n.
| a | 6 | 8 | q | 25 |
| b | 18 | p | 39 | r |
