Question

the mean of the ages of 5 brothers is 13 years. If the ages of four of the brothers are 12, 16, 14, and 8, how old is the fifth brother

Answer 1

Brothers

1. 12

2. 16

3. 14

4. 8

5. ?

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mean of the ages of 5 brothers is 13 years

$13\text{ = }\frac{12\text{ + 16 + 14 + 8 + x}}{5}$

$13\cdot5\text{ = x + 50}$

$65-50\text{ = x }$$\text{ x = 15 }$