The original number ratio of team a and team B is 7:3. After some people are transferred from team a, the number ratio of team a and team B is 3:2. Team B has 120 people. How many people are there in team B?

The original number ratio of team a and team B is 7:3. After some people are transferred from team a, the number ratio of team a and team B is 3:2. Team B has 120 people. How many people are there in team B?

Friend, let me have a try
If team B has x people, team a has 7 / 3x,
Set up team B and transfer in y people, so there is
y+x=120
7/3x-y/120=3/2
Team B x = 90 transferred to team a y = 30 original 210 people

To build a highway, it takes 100 days for team a to build it alone, and 120 days for team B to build it alone,
How many days will it take to finish the calculation

[1 - (1 / 120 * 40)] / (1 / 100 + 1 / 120) ≈ 36.36 = 37 (days)

To build a highway, team a will complete it in 100 days and team B will complete it in 150 days. If the two teams cooperate, how many days will it take to complete it

Analysis: if the total amount of project is regarded as unit 1, then the efficiency of team a is 1 / 100 and that of team B is 1 / 150
Then the number of days needed for cooperation = 1 ÷ (1 / 100 + 1 / 150) = 60 days