Aptitude Time and Work Test Paper 626) A can finish a work in 8 hours, B can finish the same work in 12 hours, and C can do it in 24 hours. All the three starts work at 3 am, 4 am, and 5 am respectively. At what time work will be completed?
Answer: B Explanation: Note: Assume the total work = LCM of the given time Take the LCM of hours = LCM of (8, 12, and 24) = 24 Note: One hour work = (total work/ time) Now, A's one hour work = 24/8 = 3 unit ATQ, between 3 am  4 am, A works alone and finish 3 units of work Or, between 3 am to 5 am, 8 unit of work is finished. i.e., 6 unit work = 1 hour To complete the 16 unit work, multiply both sides with 2 i.e., 12 unit work = 2 hours As we know, 6 work = 1 hour That means (2 + 2/3) hours requires after 5 am. So, time taken to complete the work is (5 +2 + 2/3) = 7:40am 27) A and B work separately in 15 hours and 12 hours respectively. Another man C can destroy the work in 4 hours. If they start doing work at 8 am, 9 am, and 11 am respectively. At what time the total work will be destroyed?
Answer: C Explanation: Note: Assume the total work = LCM of the given time Take the LCM of hours = LCM of (15, 12, and 4) = 60 Note: One hour work = (total work/ time) Now, A's one hour work = 60/15 = 4 unit ATQ, between 8 am  9 am, A works alone and finish 4 units of work Destroy 6 unit works in 1 hour, or 1 unit work in 1/6 hours. Hence, at 11am + 3[2/3] hours = 2:40 pm the total work will be destroyed. 28) A can complete a wall in 30 hours. B uses 30 bricks per hour, and together they can finish the wall in 12 hours. How many bricks are in the wall?
Answer: B Explanation: Note: Assume the total work = LCM of the given time Take the LCM of hours = LCM of (30 and 12) = 60 Note: One hour work = (total work/ time) A's one hour work = 60/30 = 2 unit B alone can complete the work in 60/3 = 20 hours Hence, total bricks in the wall = 20*30 = 600 bricks 29) A and B can complete a wall in 15 and 20 hours respectively. If they work together, the wall is completed in 12 hours and they use 280 less bricks. Find the total number of bricks in the wall.
Answer: A Explanation: Note: Assume the total work = LCM of the given time Take the LCM of hours = LCM of (15 and 20) = 60 Note: One hour work = (total work/ time) A's one hour work = 60/15 = 4 bricks (A+B)'s one hour work = 4+3 = 7 bricks....................... (i) The difference between equation i and ii = 2 bricks/hour 30) The efficiency ratio of A, B, and C are 2:3:4. To finish a job A takes 10 days more than B, if they work together, the work will be completed in how many days?
Answer: A Explanation: Note: ATQ, Efficiency of A: B: C =2: 3: 4Calculate the LCM of (2, 3, and 4) = 12 Now, reciprocate the efficiencies = ½: 1/3: ¼ Multiply each with 12 and we get time ratio Time ratio of A: B: C = 12 *[1/2]: 12*[1/3]: 12*[1/4] = 6: 4: 3 The difference between A and B's time ratio = 2, but ATQ, it is 10 Aptitude Time and Work Test Paper 1 Aptitude Time and Work Test Paper 2 Aptitude Time and Work Test Paper 3 Aptitude Time and Work Test Paper 4 Aptitude Time and Work Test Paper 5 Aptitude Time and Work Test Paper 7 Aptitude Time and Work Test Paper 8 Aptitude Time and Work Test Paper 9 Time and Work Concepts
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