Class 7 Math Creative : Chapter - 2.3

                      Math creative (Chapter -2.3)

1.      To produce 5000 bricks 42 workers require 30 days.

a)     To produce the same number of bricks how much time is required by a worker?

b)     To produce 100000 bricks in a month, how many workers are required?

c)     If one worker’s daily wage is 200 taka, then how much money is required to produce 100000 bricks in a month?

2.      Three friends Johir, Mihir and Sishir can do a work in 6 days, 8 days and 12 days respectively.

a)     In one day what part of work they do separately?

b)     In how many days together they can do the work?

c)     After 2 days starting the work together Johir and Mihir left the work. In how many days Sishir can finish the work alone?

3.      There is a water tank on the roof of your school. In that tank there are three pipes. With the first and second pipes the tank can be filled in 20 minutes and 30 minutes respectively. The third pipe can empty the tank in 60 minutes.

a)     In 1 minute what part of the tank is emptied by the third pipe?

b)     In 1 minute what part of the tank is filled by the first and second pipes separately?

c)     If three pipes arte open in how many minutes the tank can be filled?

4.      With the help of current a boat can reach to Dhaka from Chandpur in 10 hours. But in against water it requires 20 hours to reach Chittagong from Dhaka.The speed of the boat in still water is 21 km/h.

a)     What do you mean by the speed of the boat with current and against current?

b)     What is the distance between Chandpur and Dhaka?

c)     Find out the actual speed of the boat with and against the current.

5.      Aziz and kamal can make a wall in 20 days. After making the wall together for 12 days Aziz has finished the work in 10 days.

a)     In one day what portion of the wall can Aziz and kamal make?

b)     What portion of the work is left?

c)     If Aziz and kamal would do the work separately, in how how many days they would make the wall individually?

6.      The ratio of production cost and transportation cost of a product is 6:1. While carrying the product to a 192 km distance, truck, van and boat are used and there ratio of fare is 5:2:1.

a)     How many km of the distance was the product carried by the boat?

b)     If the costing of truck, van and boat for 1 km are Tk. 40 , Tk. 50 and Tk. 30 respectively , what is the total cost of carrying the product?

c)     If the seller wanted to sell the product at 15% profit on the whole, what would be it’s selling price?

7.      Mr. Jashim is a contractor. He gets a job to repair 2 km road in 30 days for Tk. 2 lac. To do this work he appointed 20 workers. But after 12 days the work had to close for 4 days for bad weather. After finishing the repairing, it is seen that the costing is Tk. 2, 25,000. Under this circumstances, give the answer of the following questions.

a)     What percentage of the road was repaired in 12 days?

b)     How many extra workers were needed to finish the work on time?

c)     What is the percentage of extra workers as compared with the number workers appointed earlier?

d)     To finish the repairing work, what is the percentage of his loss?

8.      A boatman was moving to one part from another part of the river with the help of boat. He can cross 3 km in 15 minutes along with current whereas he can cross 1 km in 15 minutes against the current.

a)     What do you mean by the speed of the boat along with current and without current.

b)     Find out the actual speed of the boat and current.

c)     If the actual speed of the boat in still water is 10 km/hr, then what will be the ratio of the speed of the boat with current and against current?

9.      A 120 metre long train will cross 330 metre long bridge. The speed of the train is 30 km per hour.

a)      To cross the bridge, what distance will the train cross?

b)      How long it will take to cross the bridge ?

c)      If the speed of the train is increased by 10km/hr and it will cross a platform in the time obtained from ‘b’ , what will be the length of the platform?

10. There is a tank on the roof of house. The inlet tank can fill the whole tank in 25 minutes. On the other hand, the outlet tank empty the tank in 50 minutes.

a)     If the two pipes are opened together, in 1 minutes what portion of the tank will be filled?

b)     Now, half of the tank is empty. In how many hours will the tank be filled if the two pipes are opened together?

c)     The two pipes are opened together and after 10 minutes, 2^nd pipe is closed. In how many minutes the 1^st pipe will fill the rest of the portion of the tank.