Haryana Police Constable Model Paper 4

Given:
Mean of 13 numbers is 24.
Now 3 added to each number
Formula Used:
Mean $=\frac{\mathrm{Total}\mathrm{of}\mathrm{observation}}{\mathrm{Number}\mathrm{of}\mathrm{observation}}$
Calculation:
Mean $=\frac{\mathrm{Total}\mathrm{of}\mathrm{observation}}{\mathrm{Number}\mathrm{of}\mathrm{observation}}$
$\Rightarrow 24=\frac{\mathrm{total}\mathrm{of}\mathrm{observation}}{13}$
⇒ Total of observation = 13 × 24
⇒ Total of observation = 312
Now 3 is added to all 13 numbers.
⇒ New total = 312 + 13(3) = 312 + 39 = 351
New mean $=\frac{351}{13}$
⇒ New mean = 27
∴ The new mean will be 27.