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 and B take 6 hours and 9 hours respectively to complete a work. A works for 1 hour and then B works for two hours.
(i) How much work is done in these 3 hours?
(ii) How much work is still left?
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 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?
A man walks a distance of 5 km in 2 hours. Then he goes in a bus to a nearby town, which is 40 km, in further 2 hours. From there, he goes to his office in an autorickshaw, a distance of 5 km, in `1/2` hour. What was his average speed during the whole journey?
These log boats do not go very far. If the wind is helpful, then travel about 4 km in one hour.
How long will they take to go a distance of 10 km?
Name two things that are lying to your west.
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?
What is the correct relationship between speed (S), distance (D), and time (T)?
The SI unit of speed is:
A runner covers 900 m in 3 min. Speed in m s⁻¹ is:
