Question

7. In a school, students thought of planting trees tu
pollution. It was decided that the number of trees, that each section of each class win
plant, will be the same as the class, in which they are studying, e.ge a section of Class
will plant 1 tree, a section of Class II will plant 2 trees and so on till Class XIL There are
three sections of each class. How many trees will be planted by the students?​

Answer 1

Answer:

Number of Trees Planted =Class×3

Class 1=3

Class 2=6

Class 3=9

It is clear that a=3,d=3 and n=12

By using

S

n

=

2

n

[2a+(n−1)d] we have

S

12

=

2

12

(6+3×11)=234