TCS Ninja Averages Questions and Answers Part 1

Sum of 10 even numbers = 10 * 11 = 110

Average = 110/10 = 11

1 to 11 = 11 * 10.9 = 119.9

1 to 6 = 6 * 10.5 = 63

6 to 11 = 6 * 11.4 = 68.4

63 + 68.4 = 131.4 – 119.9 = 11.5

6th number = 11.5

3x + 5x + 7x = 45

x =3

3x = 9

A + B + C = 48

B + C + D = 45

A + D = 13

A – D = 3

A + D = 13

2D = 10

D = 5

1 to 9 = 9 * 9 = 81

1 to 5 = 5 * 10 = 50

5 to 9 = 5 * 8 = 40

5th = 50 + 40 = 90 – 81 = 9

The avg. of 10 numbers is = 15

Sum of 10 numbers are = 15×10=150

He mistakenly writes one number 26 instead of 36.

∴ difference = 36 - 26 = 10

∴ Actual sum of 10 numbers = 150 + 10 = 160

∴ Actual average = 160/10=16

 

Age of husband=H
Age of wife =W
Age of child =C
((H-5)+W-5))/2=23
H+W=56
(H+W+C)/3=20
C=4yr

a= (16(a-3)+35)/17

multiply both sides by 17
17a = 16(a-3) + 85
17a = 16a - 48 + 85
17a - 16a = 37
a = 37 his average after 17 innings

Let the attendance on the three days be 2x, 5x and 13x respectively.
Then, total charges
= Rs. (15 × 2x + 7.50 × 5x + 2.50 × 13x)
= Rs. (30x + 37.5x + 32.5x)
= Rs. 100x
∴ Average change per person
= Rs.

let the average of 25 person be x

total age of a person=average×no.of person

total age of 25 person=X×25

=25X

when a new person of 46kg come average decrease by 5kg(X-5)

Total age of 26 person =25x+46

Average age of 26 person=X-5

A/Q

.25X+46=26(X-5)

25X+46=26X-130

26X-25X=130+46

X =176

hence the average of 25 person be 176kg