A group of 210 students appeared in some test. The mean of 1/3rd of students is found to be 60. The mean of the remaining students is found to be 78. The mean of the whole group will be:

Correct option is A

Given:
Total students = 210
1/3 of students = 70
Mean of 70 students = 60
Remaining students = 140
Mean of 140 students = 78
Formula:
Combined Mean = {(n₁ × Mean₁) + (n₂ × Mean₂)} / (n₁ + n₂)
Solution:
Combined Mean
= {(70 × 60) + (140 × 78)} / 210
= {4200 + 10920} / 210
= 15120 / 210
= 72
Final Answer:
(a) 72