1 The average of 20 numbers is zero. Of them, at the most, how many may be greater than zero ? A) 0 B) 1 C) 10 D) 19
3 A student was asked to find the arithmetic mean of the numbers 3, 11, 7, 9, 15, 13, 8, 19, 17, 21, 14 and x. He found the mean to be 12. What should be the number in place of x ? A) 3 B) 7 C) 17 D) 31
4 The average of 2, 7, 6 and x is 5 and the average of 18, 1, 6, x and y is 10. What is the value of y ? A) 5 B) 10 C) 20 D) 30
5 If the mean of 5 observations x, x + 2, x + 4, x + 6 and x + 8 is 11, then the mean of the last three observations is : A) 11 B) 13 C) 15 D) 17
6 The average of the two-digit numbers, which remain the same when the digits interchange their positions, is : A) 33 B) 44 C) 55 D) 66
7 The average age of the boys in a class is 16 years and that of the girls is 15 years. The average age for the whole class is : A) 10 years B) 15.5 years C) 16 years D) Data inadequate
8 A library has an average of 510 visitors on Sundays and 240 on other days. The average number of visitors per day in a month of 30 days beginning with a Sunday is : A) 250 B) 276 C) 280 D) 285
9 The average weight of 16 boys in a class is 50.25 kgs and that of the remaining 8 boys is 45.15 kgs. Find the average weight of all the boys in the class. A) 47.55 kgs B) 48kgs C) 48.55 kgs D) 49.25 kgs
10 The average of six numbers is x and the average of three of these is y. If the average of the remaining three is z, then : A) x = y + z B) 2x = y + z C) x = 2y + 2z D) None of these
11 The batting average for 40 innings of a cricket player is 50 runs. His highest score exceeds his lowest score by 172 runs. If these two innings are excluded, the average of the remaining 38 innings is 48 runs. The highest score of the player is : A) 165 runs B) 170 runs C) 172 runs D) 174 runs
12 A grocer has a sale of Rs. 6435, Rs. 6927, Rs. 6855, Rs. 7230 and Rs. 6562 for 5 consecutive months. How much sale must he have in the sixth month so that he gets an average sale of Rs. 6500 ? A) Rs. 4991 B) Rs. 5991 C) Rs. 6001 D) Rs. 6991
13 Of the three numbers, the average of the first and the second is greater than the average of the second and the third by 15. What is the difference between the fire and the third of the three numbers ? A) 15 B) 45 C) 60 D) Data inadequate E) None of these
14 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 : Rs. 27.50
15 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