Advertisements
Advertisements
Question
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?
Solution
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
RELATED QUESTIONS
A school has 8 periods a day each of 45 minutes duration. How long would each period be, if the school has 9 periods a day, assuming the number of school hours to be the same?
In which of the following table x and y vary inversely:
| x | 4 | 3 | 6 | 1 |
| y | 9 | 12 | 8 | 36 |
Which of the following quantities vary inversely as other?
Journey (x km) undertaken by a car and the petrol (y litres) consumed by it.
A work force of 50 men with a contractor can finish a piece of work in 5 months. In how many months the same work can be completed by 125 men?
18 men can reap a field in 35 days. For reaping the same field in 15 days, how many men are required?
If xy = 10, then x and y vary ______ with each other.
When two quantities x and y are in ______ proportion or vary ______ they are written as `x oo 1/y`.
If x varies inversely as y, then
| x | – | 60 |
| y | 2 | 10 |
If a tree 24 m high casts a shadow of 15 m, then the height of a pole that casts a shadow of 6 m under similar conditions is 9.6 m.
Write whether the following statement vary directly, vary inversely with each other, or neither of the two.
Compound interest on a given sum and the sum invested.
