Question

1. The average age of three friends 3 years ago was 63 years. The average age of

two of them 5 years ago was 50 years. What is the present age of the third

friend? (Let the present age of the three people be x, y, z. The average age of

the three people 'n' years ago is given. The average age of two people m years

ago is also given. ((x+y+z)-(3*n))/3 = average n years ago. ((x+y)-

(2*m))/2=average m years ago. The two calculations lead to two equations, one

with two unknown variables and three unknown variables. The equation with

two unknown variables can be used in the equation with three unknown

variables. Using this, we can solve for the unknown weight of the third person.)

2. The purchase (in rupees) of a store for five consecutive days is 4265, 7827,

6587, 7012, 1302. What should be the purchase on the sixth day so that the

overall average purchase is 5743? (Let the sale on the sixth day be x. (sum of

the sales of five days+x)/6=overall average sale. Solve for x.)

3. The average weight of the 6 boxes increases by 28 Kg when a new box replaces

a box of weight 14 Kg. What is the weight of the new box? (Total increase in

weight = (number of boxes*increase in average weight). Weight of new box =

(weight of old box + total increase in weight)

4. 305 men and 197 women are employed in a factory. The average wage per

person is Rs. 233. What is the wage of a man if women are paid Rs. 5 less? (Let

wage of a man be a and wage of a woman be (a-difference in wage). Average

wage per person = ((a*number of men)+((a-difference in wage)* the number of

women))/(sum of the number of men and women). Solve for a.)

5. What is the increase in the average of 11 numbers if the number 11 is replaced

by 55? (Increase/decrease in average = (New value - original value)/number of

items)

6. What is the average of the first 219 natural numbers? (Sum of first n natural

numbers = (n*(n+1))/2. Average = Sum/number of items.)

7. The average weight of 13 students of a class is 49 Kg, whereas the average

weight of the remaining 20 students is 48 Kg. What is the average weight of all

33 students? (Total weight of n students = n * average weight of n students.​

Answer 1

Answer:

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