The average mass of a group of 3 boys is 38 kg. Hashim, whose mass is 42 kg, joined the group. What is the average mass of the new group?

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Worked solution

1. Calculate the total mass of the original 3 boys

$\text{Total mass of 3 boys} = 3 \times 38 = 114 \text{ kg}$

2. Calculate the new total mass after Hashim joins

$\text{New total mass} = 114 + 42 = 156 \text{ kg}$

3. Calculate the new average mass

$\text{New average mass} = \frac{156}{4} = 39 \text{ kg}$

Answer

$39$ kg (option 2)

AI analysis — may contain mistakes.

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