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CBSE Worksheet for Chapter - 7 Time and Work Class 8

Worksheets For class 8

Find CBSE Worksheet for chapter-7 Time and Work class 8

CLASS-8

BOARD: CBSE

Mathematic Worksheet - 7

TOPIC: Time and Work

For other  CBSE Worksheet for class 8 Mathematic  check out main page of Physics Wallah.

SUMMARY:

Unitary method and complex ratio:

1) Direct proportion: Two quantities are said to be directly proportional, if on the increase (or decrease) of one, the other increases (or decreases) to the same extent.

2) Indirect proportion: Two quantities are said to be indirectly proportional, if on the increase of one, the other decreases to the same extent and vice-versa.

Work and Time:

If A can do a piece of work in m days, then A’s 1 day work is  1/m.

EXERCISE:

1) 24 men can complete a given job in 40 days. Then find the number of men required to complete the j ob in 32 days

A) 25men

B) 30 men

C) 32 men

D) 35 men

2) If 5 men can cane 5 chairs in 5 hours, then 1 man shall can 1 chair in how many hours?

A) 1hour

B) 15hours

C) 5 hours

D) 10hours

3) If 4 workers can dig 20m long ditch in 6 days, find the part dug by 2 workers in a day(in meter).

A) 5/3

B)14/4

C) 11/3

D) 5/2

4) 25 men were employed to do a piece of work in some days. After 15 days, 10 more men were engaged and the work was finished in 23 days. In what time would they finish the work if extra men were not employed?

A) 24 days

B) 24.6 days

C) 26.2days

D) none

5) If 12 men or 18 women can reap a field in7 days. In what time can 4 men and 8 women reap the same field?

A) 8 days

B) 8 days

C) 10 days

D) none

6) A and B together can complete a work in 12 days. A alone can complete it in 20 days. If B now does the work for half a day daily then in how many days A and B together will complete the work?

A) 15 days

B) 20 days

C) 45 days

D) 30 days

7) A can do a piece of work in 9 days and B in 18 days. They began the work together but 3 days before the completion of the work, A leaves. The time taken to complete the work is:

A) 7 days

B) 5 days

C) 8 days

D) 11 days

8) A, B, C can complete a piece of work in 24, 6 and 12 days respectively. Working together, they will complete the same work in:

A) 1/24 day

B) 7/24 day

C) 24/7 days

D) 4 days

9) A, B, C can finish a piece of work in 4 days. A alone can do it in 9 A, B, C can complete a piece of work in 24, 6 and 12 days and B in 18 A, B, C can complete a piece of work in 24, 6 and 12 days. How many days will be taken by C to do it alone?

A) 15 days

B) 14 days

C) 12 days

D) 10 days

10) A takes twice as much time as B and thrice as much time as C to finish a piece of work. Working together, they can finish the work in 2 days. B can do the work alone in:

A) 4 days

B) 6 days

C) 8 days

D) 12 days

11) 4 pipes can fill a tank in 15, 20,30 and 50 hours respectively. The first was opened at 6 a.m., second at 7 a.m., third at 8 a.m. and fourth at 9 a.m. When will the tank be full?

A) 12.30p.m

B) 1 pm

C) 2 pm

D) none

12) Taps A and B can fill a tank in 12 min and 15 min respectively. If both are opened and A is closed after 3 min, how long will it take for B to fill the tank?

A) 7min 45 s

B) 7min 15 s

C) 8min 5 s

D) 8min 15 s

13) A leak in the bottom of the tank can empty it in 6 hr. A pipe fills the tank at 4L/min. When the tank is full, the inlet is opened, but due to the leak the tank is emptied in 8 hr. What is the capacity of the tank?

A) 5260L

B) 5760L

C) 5846L

D) 6970L

14) Certain number of persons can complete a work in 100 days. If 10 persons were less, it would have taken 10 days more for the work to be completed. Number of persons in the beginning is:

A) 100

B) 90

C) 110

D) None

15) A woodcutter cuts a log of wood in three pieces in 18 minutes. To make x such pieces, the time taken will be:

A) 6(x-1) minutes

B) 6x minutes

C) 9(x-1) minutes

D) 9x minutes

Solutions: to worksheet-7 Topic- Time and Work

1) (B)

2) (C)

3) (A)

4) (C)

5) (B)

6) (A)

7) (C)

8) (C)

9) (C)

10) (B)

11) (B)

12) (D)

13) (B)

14) (C)

15 (C)

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