Saturday, August 3, 2013

10-chain rule / time and work

A student hostel has 280 students. It has ration for 20 days. 40 students leave for home on Christmas after 8 days of staying together. How many days will the ration last?

9- chain rule / time and work

3 men or 5 boys can do a piece of work in 30 days. In how many days will 5 boys and 12 men do the job?

chain rule

In a hostel, ration for 2000 students is sufficient for 54 days. After 15 days some more people join in and the ration lasted for only 20 more days. How many people joined in later?

chain rule

48 men working 4 hours a day can complete the work in 10 days. How many men will be required to complete the work in 6 days, working 10 hours a day?

chain rule / unitary method

40 girls can make 30 boxes in 20 days. How many more girls should be employed to prepare 60 boxes in 25 days?

chain rule / unitary method

If 16 pens cost Rs 240 what will be the cost of 18 pens?

Chain rule / unitary method

If 12 books cost Rs 80 what will be the cost of 30 books?

(alternate to unitary method)

distance and speed



A man can row 15 km/hr in still water. It takes him twice as long to row upstream than to row downstream. What is the speed of the stream?

distance and speed



A boat rows from place A to B in 4 hours and returns back in 5 hours. The speed of the stream is 2 km/hr. What is the speed of the Boat in still water?

distance and speed



A boat can row upstream at 12 km/hr and downstream at 24 km/hr, what is the speed of the boat?

distance and speed



A man can row at 10 km/hr in still water. In a steam that is flowing at 4 km/hr, it takes him 2 hours to row to the place and back to where he started from. How far is the place?

Friday, August 2, 2013

distance and speed

Two men ride towards each other from two places 80 km apart, one at 18 km/hr and the other at 14 km/hr. Find when they are first 16 km apart. Also find when they will be16 km apart for the second time.

simple equation

A's age is equal to the sum of the ages of B and C. Ten years ago A was twice as old as B. Show that 10 years hence A will be twice as old as C.


Distance and speed

A and B start at noon from two towns 60 km apart, A's rate of walking being twice B's. If they take 5 hours before they meet, find their rates of walking.

simple equations

A man's age is 3 times the sum of the ages of his two sons, one of whom is twice as old as the other; in 12 years the sum of the son's ages will be three fourth of their father's age. Find the age of the father.

simple equation

A is 12 years older than B; 12 years ago he was twice as old as B then was. How old is A now?

simple equation

In 17  years a father will be twice as old as his son, whose age at the present time is one third of his father age. How old is his father now?


distance and speed



Two trains are moving in the same direction at a speed of 32 km/hr and 40 km/hr. The faster train crosses a man in the slower train in 36 secs.  What is the length of the faster train?

distance and speed



Two trains cross each other in 30 secs when they are running in the opposite direction. The speed of the two trains is 40 km/hr and 32 km/hr. If the length of the first train is 280 metres, then find the length of the second train?

distance and speed



Two trains of 200 metres and 240 metres length are running in the same direction. They take 180 secs to cross each other. The speed of the slower train is 54 km/hr. What is the speed of the other train?