# Question #7a122

##### 1 Answer

Harry has a mass of 44 Kg and Bruce has a mass of 39 Kg

#### Explanation:

There are 3 different masses involved - we need to be able to write 3 different equations to find them.

Define the variables first.

Let

Find Bruce's mass in terms of the other masses: Note: b=b

We now know that the boys' masses add up to 83 and differ by 5.

Add the two equations together:

Bruce's mass

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An alternative method :

We now know that the boys' masses add up to 83 and differ by 5.

Subtract the difference from the total of the masses and divide by 2.

The two masses are therefore