Advertisements
Advertisements
प्रश्न
Joseph and Peter can complete a work in 20 hours and 25 hours respectively. Find :
(i) work done by both together in 4 hrs.
(ii) work left after both worked together for 4 hrs.
(iii) time taken by Peter to complete the remaining work.
Advertisements
उत्तर
Joseph can do a work in = 20 hours
Peter can do the same work in = 25 hours
Now Joseph's 1 hour's work = `1/20`
and Peter's 1 hour's work = `1/25`
Both's 1 hour's work = `1/20 + 1/25 = (5 + 4)/100 = 9/100`
(i) Both's 4 hours work `= 9/100 xx 4 = 9/25`
(ii) Work left over `= 1 - 9/25`
`= (25 - 9)/25 = 16/25`
(iii) Peter can do `16/25` work in `= 25 xx 16/25` = 16 hours
APPEARS IN
संबंधित प्रश्न
A is able to complete `1/3` of a certain work in 10 hrs and B is able to complete `2/5` of the same work in 12 hrs. Find:
(i) how much work can A do in 1 hour ?
(ii) how much work can B do in 1 hour ?
(iii) in how much time will the work be completed, if both work together.
Shaheed can prepare one wooden chair in 3 days and Shaif can prepare the same chair in 4 days. If they work together, in how many days will they prepare:
(i) one chair?
(ii)14 chairs of the same kind?
A, B and C together finish a work in 4 days. If A alone can finish the same work in 8 days and B in 12 days, find how long will C take to finish the work.
A motorist travelled the distance between two towns, which is 65 km, in 2 hours and 10 minutes. Find his speed in metre per minute.
A train travels 700 metres in 35 seconds. What is its speed in km/h?
A racing car covered 600 km in 3 hours 20 minutes. Find its speed in metre per second. How much distance will the car cover in 50 sec?
Jagan went to another town such that he covered 240 km by a car going at 60 kmh-1. Then he covered 80 km by a train, going at 100 kmh-1 and the rest 200 km, he covered by a bus, going at 50 kmh-1. What was his average speed during the whole journey?
The speed of sound in air is about 330 ms-1. Express this speed in kmh-1. How long will the sound take to travel 99 km?
Look at the different types of boats.
Some boats have motors and go further into the sea. since they go far out they can catch more fish. These boats travel faster, at a speed of about 20 km in one hour.
How much time will they take to go 85 km?
The SI unit of speed is:
