Time And Work

31 P and Q can do a piece of work in 30 and 40 days respectively. They began the work together, but P left after some days and Q finished the remaining work in 12 days. After how many days did P leave?

32 A, B and C can do a piece of work in 20, 30 and 60 days respectively. In how many days can A do the work if he is assisted by B and C on every third day?

33 12 men can do a piece of work in 24 days. How many days are needed to complete the work, if 8 men do this work?

34 30 men can plant 60 trees in 5 hours. If 5 men leave the job, how many trees will be planted in 10 hours?

35 P and Q can do a piece of work in 12 days, Q and R in 15 days, R and P in 20 days. How long would P,Q AND R take separately to do the same work respectevilly?

36 A and B can do a piece of work in 3 days. B and C can do the same work in 9 days, while C and A can do it in 12 days. Find the time in which A, B and C can finish the work, working together:

37 P is twice as good a workman as Q, and together they finish a work in 16 days. In how many days can it be done by each separately?

38 12 men complete a work in 9 days. After they have worked for 6 days, 6 more men join them. How many days will they take to complete the remaining work?

39 In a hostel, there are 120 students and food stock is for 45 days. If 30 new students join the hostel, in how many days will the complete stock be exhausted?

40 In a school, Mid-Day Meal food is sufficient for 250 students for 33 days, if each student is given 125 g meals. 80 more students joined the school. If same amount of meal is given to each student, then the food will last