The average weight of a class of 40 students is 40 kg. If the weight of the teacher be included , the average weight increases by 500 gm . The weight of the teacher is?

Weight increase = 8 x 2 kg = 16 kg
weight of new man= 50 + 16 = 66 kg

Let the total number of workers be y.
So sum of salary for all workers = sum of salary of 7 technician + sum of salary for other y -7 workers.
7 x 1000 + 780(y -7) = 850 y
? 7000 + 780y - 5460 = 850y
? 70y = 1540
? y = 22

So total number of workers = 22

Total earning for the week = Sum of earning of first four days + Sum of earning of last four days - Earning of 4th day
= 4 x18 + 4 x 22 -20
= Rs. 140

? Average earning = 140 / 7
= Rs. 20

Let third number = y
Then, second number = 2y
and first number =4y

? ( y + 2y + 4y) / 3 = 42
? 7y = 42 x 3
? y = 18

so, (largest) - (smallest) = ( 4y - y)
= 3y
=54

Let the present ages of father be 3x and daughter be x .
so the 4 year ago father's age and daughter's age was
( 3x - 4 ) and ( x - 4 )
? ( 3x - 4 / x -4 ) = 4 / 1
? x = 12 year and 3x = 36 year

New average = 120% of old average
=120% of 18.5
= (120 x 18.5) / 100
= 22.2

Age of coach = Total weight of 4 players and coach - total weight of 4 players
= 5 x 22.2 - 4 x 18.5
= 37 years

Let the age of youngest child be y.
so from question y + (y + 4) + (y + 8) + (y + 12) = 4 x 12
? 4y + 24= 48
? y = 6 years

Production during these 5 days = Total production in a month - production in first 25 days.
= 30 x 58 - 25 x 60
= 240
? Average for last 5 days = 240 / 5
= 48

Let the number of candidate who passed = y
Then, 39y + 15(120 - y) =120 x 35
? 24y= 4200 -1800
? y= 2400 / 24 = 100

Let average of the remaining student be y.
Then from questions ( 5 x 10 ) + ( 5 x 14) + 20y = 30 x 12
? 50 + 70 + 20y = 360
? 20y = 360 ? 120
? 20y = 240
? y = 12.