EXERCISE 6.A (OBJECTIVE TYPE QUESTIONS) (IN 81 85 SOLUTION)

81.       A certain factory employed 600 men and 400 women and the average wage was Rs. 25.50 per day. If a woman got Rs. 5 less than a man, then what are their daily wages?

a)      Man: Rs. 25; woman : Rs. 20

b)      Man : Rs. 27.50, woman: Rs. 22.50

c)       Man: Rs. 30, woman : Rs. 25

d)      Man: Rs. 32.50, woman:  27.50.

82.       The arithmetic mean of the scores of a group of students in a test was 52. The brightest 20 % of them secured a mean score of 80 and the dullest 25% a mean score of 31. The mean score of remaining 55% is:

a)      45

b)      50

c)       51.4 approx.

d)      54.6approx.

83.       The average salary of all the workers in a workshop is Rs. 8000.Thhe average salary of 7 technicians is Rs. 12000 and the average salary of the rest is Rs. 6000. The total number of workers in the workshop is:

a)      20

b)      21

c)       22

d)      23

84.       In a school with 600 students, the average age of the boys is 12 years and that of the girls is 11 years. If the average age of the school if 1 years 9 months, then the number of girls in the school is:

a)      150

b)      250

c)       350

d)      450

85.       In an examination, a pupil’s average marks were 63 per paper. If they had obtained 20 more marks for his Geography paper and 2 more marks for his History paper, his average per paper would have been 65. How many papers were there in the examinations?

a)      8

b)      9

c)       10

d)      11

e)      12

86.       The average age of students of a class is 15.8 years. The average age of boys in the class is 16,.4 years and that of the girls is 15.4 years. The ratio of the  number of boys to the number of girls in the class is

a)      1: 2

b)      2:3

c)       3:4

d)      3:5

ANSWERS

81.B

82.C

83.B

84.A

85.D

86.B

SOLUTION 

81.       Let the daily wage of a man be Rs. X.

Then, daily wage of a woman = Rs. (X -5).

Now, 600x + 400 ( X – 5) = 25.50 x (600 + 400)   1000x = 27500    x = 27.50.

Man’s daily wages = Rs. 27.50; woman’s daily wages = (x – 5) = Rs. 22. 50.

82.       Let the required mean score be X. then,

20 x 80 + 25 x 31 + 55 x X = 52 x 100

1600 + 775 + 55x = 5200   55X = 2825     x = 565 / 11 = 51.4.

83.       Let the total number of workers be x. then,

8000x = (12000 x 7) + 6000 ( x -7)    2000x = 42000   x = 21.

84.       Let the number of girls be x. then, number of boys = (600 –X).

Then, (11  ¾ x 600) = 11X + 12 (600 –X)    7200 -7050   x = 150.

85.       Let the number of papers be x. then, 63x + 20 + 2 = 65x or 2X = 22 or = 11.

86.       Let the ratio be K; 1. Then,

K x 16.4 + 1 x 15.4 = (k + 1) x 15.8

(16.4 – 15.4) k = (15.4 – 15.4)   k = 0.4 /0.6 = 2/3.

Required ratio = 2/3 : 1 = 2:3