There are 34 students in a class. The average weight of the class is 35 kg. If two new students joined the class, the average weight increases by 2 kg. Find the total weight of the two new students who joined the class?

Option 2 : 142 kg

Given

Average weight of 34 students of a class = 35 kg.

Formula used∶

Average = sum of observations/total number of observations

Calculation∶

Total sum of weights = 34 × 35 = 1190 kg

Let the total weight of the two new students be ‘x’ kg.

When two new students are included average weight increases by 2 kg.

⇒ 36 × (35 + 2) = 1190 + x

⇒ 1332 = 1190 + x

⇒ x = 142 kg

∴ Total weight of two new students is 142 kg

Shortcut Trick

Total Weight of two new students = (Increased Average × no. of people in group + Number of new people joined × old average)

= (2 × 36 + 2 × 35) = 142 kg