Average weight of 20 persons is x kg. Two person’s weights 42kg and 44 kg are wrongly entered as (x – 8) kg and (2x/3 + 4)

Average weight of 20 persons is x kg. Two person’s weights 42kg and 44 kg are wrongly entered as (x – 8) kg and (2x/3 + 4) and when the average weight is calculated with the correct weight, then the average weight increases by 0.5kg. Find the value of x.

a)            48

b)            44

c)            40

d)            36

e)            None of these

Sol:

Total weight of 20 persons = 20 * x

(20x – (x – 8) – (2x/3 + 4) + 42 + 44)/20 = x + 0.5

20x – x + 8 – 2x/3 – 4 + 86 = 20x + 10

– x – 2x/3 + 90 = 10

5x/3 = 80

x = 48