(3/4- 1/ 10 * 2)/( 1/ 10+ 1/ 15) = 1 1/20/(65438
12, there is a job that Xiaohua needs 3 days to do, Xiao Fang needs 4 days to do and Xiaomei needs 5 days to do. If three people work together, how many days will it take to finish?
1/(1/3+1/4+1/5) = 60/47 days.
13. For a project, it takes 10 days for Team A to do it alone, 4 days for Team A and Team B to do it together, and how many days for Team B to do it alone?
1/(1/4-110) = 20/3 days.
14. It takes 6 days for Party A to do a job alone, 8 days for Party B, and 3/4 of the work can be completed by two people working together for several hours?
3/4/(1/6+1/8) =18/7 days.
15, a project, 60 days for Team A and 40 days for Team B.. Now 10 days later, team b also took part in the work. How many days will it take to complete?
(1-1/60 *10)/(1/60+1/40) = 20 days.
16, there is a project, it takes 10 days for Team A to do it alone, and it takes 4 days for Team A and Team B to do it together. If Team A does it for three days first, how many days will it take for the two teams to do it together?
4 * (1-110 * 3) = 2.8 days.
17.a typist can type a manuscript for four hours, while b can type it for eight hours. Two hours together, and the rest is played by B alone. How many hours will it take?
8 * (1-1/4 * 2-1/8 * 2) = 8 *1/4 = 2 hours.
18, a batch of goods, trucked 18 times, trucked 30 times. How many times can the same three trucks and five carts be transported together?
1/(3/ 18+5/30)=3 times.
19. Team A will finish a project in 30 days, and Team B will finish it in 20 days .. (1) How many times can two teams finish the project in 5 days? ( 1/30+ 1/20)*5=5/ 12
(2) The two teams cooperated for 10 days. How much is left in the project? ( 1/30+ 1/20)* 10=5/6
(3) How many days do the two teams work together? 1/(1/30+1/20) =12 days.