The mean of 6 different data is 12. If 5 of these data are 16, 18, 12, 13 and 8; the sixth data is :

1. 63

2. 6 × 12

3. 5

4. 12 × 3

Given,

Mean of 6 different data is 12.

By formula,

$\Rightarrow \text{Mean } = \dfrac{\text{Total value}}{\text{No. of observations}} \\[1em] \Rightarrow 12 = \dfrac{\text{Total value}}{6} \\[1em] \Rightarrow \text{Total value} = 12 \times 6 = 72.$

Given,

16, 18, 12, 13 and 8. Let sixth data be x.

So,

⇒ 16 + 18 + 12 + 13 + 8 + x = 72

⇒ x + 67 = 72

⇒ x = 72 - 67 = 5.

Hence, Option 3 is the correct option.