Standard Mathematics Primary 6 Average

The average mass of 4 boys is 38 kg. When a fifth boy joins them, the average mass of the 5 boys becomes 40 kg. Find the mass of the fifth boy.

A 50 kg
B 40 kg
C 10 kg
D 48 kg
Show Worked Solution

Worked Solution

Step 1: Find the total mass of the original 4 boys. Total of 4 boys = 4 × 38 = 152 kg. Step 2: Find the total mass of all 5 boys after the fifth joins. Total of 5 boys = 5 × 40 = 200 kg. Step 3: The mass of the fifth boy is the difference. Mass of fifth boy = 200 − 152 = 48 kg. Answer: 48 kg

Correct answer: 48 kg

Want more questions like this? Superholic Lab has 10,000+ MOE-aligned questions with full worked solutions.

Start Free Trial — 7 Days Free