CBSE Class 10 Answered

There are three sections of each class and it is given that the number of trees planted by any class is equal to class number.

The number of trees planted by class I = number of sections 1 = 3 1 = 3

The number of trees planted by class II = number of sections 2 = 3 2 = 6

The number of trees planted by class III = number of sections 3 = 3 3 = 9

Therefore, we have the sequence: 3, 6, 9, ...., (12 terms)

To find total number of trees planted by all the students, we need to find sum of the 12 terms of the sequence.

First term = a = 3

Common difference = d = 6 - 3 = 3

n = 12

S_n= [2a+(n-1)d]

S₁₂ = [6+(12 - 1)(3)] = 6(6+33) = 6 39 = 234

Thus, in total 234 trees will be planted by the students.

Values inferred are environmental friendly and social.