Madhya Pradesh Police Exam Model Paper 6

Given:
Average weight of 12 people and the trainer = 66 kg
Calculation:
The weight of 12 students and the trainer $=13\times 66$
⇒ 858 kg
Total weight excluding the trainer $=68\times 12$
⇒ 816
The weight of the trainer
$\Rightarrow 858\mathit{–}816$
⇒ 42 kg
∴ The weight of the trainer is 42 kg.