Time and Work Class 8 MCQ Questions with Answers Maths are covered in this Article. Time and Work Class 8 MCQs Test contains 7 questions. Answers to MCQs on Time and Work Class 8 Maths are available at the end of the last question. These MCQ have been made for Class 8 students to help check the concept you have learnt from detailed classroom sessions and application of your knowledge. For more MCQ’s, subscribe to our email list.
Time and Work Class 8 MCQ Questions with Answers
1.X and Y together can do a piece of work in 6 days, while X can finish the same piece of work in 9 days. Find the number of days in which Y alone can finish the work?
(a) 24 days
(b) 30 days
(c) 18 days
Answer
Answer: (c) 18 days
Explanation: Work done by Y in one day = Work done by ( X + Y ) in one day – Work done by X in one day
Given:
Time taken by ( X + Y ) to complete the work = 6 days
Time taken by X to complete the work = 9 days
Work done by ( X + Y ) in one day = 1/6
Work done by X in one day = 1/9
Work done by Y in one day = Work done by ( X + Y ) in one day – Work done by X in one day
= (1/6) – (1/9)
= (3−2)/18
= 1/18
Since, Work to be completed and Days Taken have inverse relationship, We will just take an inverse of units produced in one day to know the time taken.
Time taken by Y to complete the work = 18 days
2.P can do a piece of work in 18 days. Q is 20 % more efficient than P. Find the number of days in which Q can finish a piece of work?
(a) 20 days
(b) 15 days
(c) 28 days
Answer
Answer: (b) 15 days
Explanation: Time taken by P to finish a piece of work = 18 days
Work done by P in one day = 1/18 units
Given:
Q is 20 % more efficient than P
i.e., Work done by Q in one day = Work done by P in one day + 20% of Work done by P in one day
= (1/18) + ( 20% of (1/18) )
= (1/18) + ( 20100 x (1/18) )
= (1/18) + (20/1800)
= (100+20)/1800
= 120/1800 units
Since, Work to be completed and Days Taken have inverse relationship, We will just take an inverse of units produced in one day to know the time taken.
Time taken by Q to finish a piece of work = 1800/120 days
= 15 days
3.P can finish a piece of work in 7 days and Q can do the same work in 21 days. Find the number of days in which total work can be completed if both of them work together?
(a) 21/4 days
(b) 17/3 days
(c) 18/7 days
Answer
Answer: (a) 21/4 days
Explanation: Time taken by P to finish the piece of work = 7 days
Time taken by Q to finish the piece of work = 21 days
Work done by P in 1 day = 1/7
Work done by Q in 1 day = 1/21
Work done by ( P and Q ) together in one day
i.e., Work done by ( P + Q ) in one day = (1/7) + (1/21)
Work done by ( P + Q ) in one day = (3+1)/21
Work done by ( P + Q ) in one day = 4/21
then, Time taken by ( P + Q ) to complete the piece of work = 21/4 days
Time and Work Class 8 MCQ Questions with Answers
4.X and Y together can do a piece of work in 10 days ; Y and Z can do it in 12 days , while X and Z can do it in 20 days . Find the number of days in which X , Y and Z can together finish the piece of work?
(a) 60/7 days
(b) 50/9 days
(c) 75/8 days
Answer
Answer: (a) 60/7 days
Explanation: Time taken by ( X + Y ) to finish a piece of work = 10 days
Time taken by ( Y + Z ) to finish a piece of work = 12 days
Time taken by ( X + Z ) to finish a piece of work = 20 days
Work done by ( X + Y ) in one day = 1/10 ———— 1
Work done by ( Y + Z ) in one day = 1/12 ———— 2
Work done by ( X + Z ) in one day = 1/20 ———— 3
Adding equation 1, 2, and 3 we get,
Work done by ( X + Y + Y + Z + X + Z ) in one day = (1/10) + (1/12) + (1/20)
Work done by ( 2X + 2Y + 2Z ) in one day = (1/10) + (1/12) + (1/20)
Work done by 2 (X + Y + Z) in one day = (6+5+3)/60
Work done by 2 (X + Y + Z) in one day = 14/60
Work done by (X + Y + Z) in one day = 14/(2×60)
Work done by (X + Y + Z) in one day = 14/120
Time taken by (X + Y + Z) to finish a piece of work = 120/14
Time taken by (X + Y + Z) to finish a piece of work = 60/7
5.P , Q and R can do a piece of work in 6 days. P and Q can do it alone in 24 days and 12 days respectively. Find the number of days in which R alone can finish the work?
(a) 12 days
(b) 24 days
(c) 48 days
Answer
Answer: (b) 24 days
Explanation: Time taken by ( P + Q + R ) to finish a piece of work = 6 days
Time taken by P to finish a piece of work = 24 days
Time taken by Q to finish a piece of work = 12 days
Work done by ( P + Q + R ) in one day = 1/6 ———— Equation 1
Work done by P in one day = 1/24 ———— Equation 2
Work done by Q in one day = 1/12 ———— Equation 3
Subtracting Equation 2 and Equation 3 from Equation 1
i.e., Equation 1 – Equation 2 – Equation 3
Work done by ( P + Q + R – P – Q ) in one day = (1/6) – (1/24) – (1/12)
Work done by R in one day = (4−1−2)/24
Work done by R in one day = 1/24
Time taken by R to finish a piece of work = 24 days
6.Tap P and Tap Q can fill a cistern in 4 hours and 16 hours respectively. If both the taps are opened simultaneously, then the cistern will be filled in?
(a) 13/2 hours
(b) 27/5 hours
(c) 16/5 hours
Answer
Answer: (c) 16/5 hours
Explanation: Time taken by Tap P to fill the cistern = 4 hours
Time taken by Tap Q to fill the cistern = 16 hours
Cistern filled by Tap P in one hour = 1/4
Cistern filled by Tap Q in one hour = 1/16
Cistern filled by Tap ( P + Q ) in one hour = (1/4) + (1/16)
Cistern filled by Tap ( P + Q ) in one hour = (4+1)/16
Cistern filled by Tap ( P + Q ) in one hour = 5/16
Time taken by Tap P and Q together to fill the cistern = 16/5 hours
7.Tap X can fill a cistern in 15 hours while tap Y can empty the full cistern in 25 hours. If both the taps are opened, then the cistern will be filled in how many number of hours ?
(a) 75/2 hours
(b) 75/3 hours
(c) 69/2 hours
Answer
Answer: (a) 75/2 hours
Explanation: Time taken by Tap X to fill the cistern = 15 hours
Time taken by Tap Y to empty the full cistern = 25 hours
Cistern filled by Tap X in one hour = 1/15
Cistern emptied by Tap Y in one hour = −1/25 ( tap Y empties the cistern )
Cistern filled by Tap ( X + Y ) in one hour = (1/15) + (−1)/25
Cistern filled by Tap ( X + Y ) in one hour = (1/15) – (1/25)
Cistern filled by Tap ( X + Y ) in one hour = (5−3/75
Cistern filled by Tap ( X + Y ) in one hour = 2/75
Time taken by Tap X and Tap Y to fill the cistern if they are opened simultaneously = 752/ hours
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