Current location - Training Enrollment Network - Mathematics courses - Five math problems
Five math problems
There are two groups in a workshop, and the ratio of the first group to the second group is 5: 3. If there are 14 people in the first group and the second group, the ratio of the first group to the second group is 1:2. How many people are in each group?

The total number of people in the two groups is regarded as the whole "1". One group accounts for 5/8, and the other group accounts for 3/8; After the number of people changes, one group accounts for 1/3, and the second group accounts for 2/3.

Total population: 1 4/(5/8-1/3) =14/7/24 = 48 (people), group/kloc-0, 48*5/8=30 (people).

2. A number of 1 equals a number of 4 1. What's the fraction of A and what's the multiple of B?

1/3/ 1/4 =4/3 (B is a multiple of a) 1/4/ 1/3 =3/4 (A is a fraction of b).

3. The school planted trees, completing 37.5% of the plan on the first day, the remaining two thirds on the second day, and planting 55 trees on the third day, exceeding the plan by 25%. How many trees do you plan to plant?

The remaining percentage on the first day is 1-37.5%=62.5%, and the remaining 2/3 accounts for 62.5%*2/3=5/ 12 of the planned percentage.

The remaining percentage is 62.5%-5/ 12 = 5/24, and the percentage of 55 trees is 5/24+25% =1/24.

55/11/24 =120 (tree)

4. The ratio of original books between A school and B school is 7: 5. If school A gives 650 books to school B, the ratio of books between school A and school B is 3: 4. How many books are there in a school? Understanding is the same as the first question.

650/(7/12-3/7) = 650/13/84 = 4200 (Ben)

5. There is a project to be done alone, team A needs 20 days, team B needs 24 days and team C needs 30 days ... Now the three teams are cooperating. However, Team A was evacuated to another construction site halfway, and it took 12 days to complete the project. When Team A retreated, how many days did it take Team B and Team C to finish?

First, make clear what percentage of all projects were completed by teams B and C within 12 days.

1-( 1/24+ 1/30)* 12= 1-9/ 10= 1/ 10

110/1/20 = 2 (days)