Hope primary school teachers and students a total of 100 people to plant trees. Teachers plant 3 trees each, students plant a tree every 3 people, a total of 100 trees. How many teachers and students?

Hope primary school teachers and students a total of 100 people to plant trees. Teachers plant 3 trees each, students plant a tree every 3 people, a total of 100 trees. How many teachers and students?

Suppose there are x teachers, then there are 100-x students. From this, we can get the equation: 3x + 13 (100-x) = 100 & nbsp; & nbsp; & nbsp; 3x + 1003-13x = 100, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 83x = 2003, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X = 25.100-25 = 75. Answer: there are 25 teachers and 75 students

The sixth grade students plant trees voluntarily. Last year, they planted 500 trees. This year, they planted 20% more trees than last year. The year before last, they planted 20% less trees than last year
2. How many trees were planted the year before last 3. How many trees were planted in three years

1. This year = 500 × (1 + 20%) = 600 trees
2. The year before last = 500 × (1-20%) = 400 trees
3. Total = 500 + 600 + 400 = 1500 trees

Students, we are planting 1800 trees this year, 20% more than last year. How many trees were planted last year?

1800/(1+20%)
=1800/1.2
=1500
1500 trees were planted last year