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:
1). 50%
2). 51.4% approx.
3). 54.6% approx
4). 45%
The average price of five different books b1, b2, b3, b4 and b5 is Rs. 450. The average price of book b1 and book b3 is Rs. 250 while average price of book b2 and book b4 is Rs. 650. Find the price of b5 book.
1). Rs. 750
2). Rs. 650
3). Rs. 500
4). Rs. 600
The average of 7 numbers is 28. The average of first three of them is 23 and the last three of them is 42. Then the fourth number is:
1). 3
2). 2
3). 1
4). 0
An average of 5 numbers is 40. If two of them are excluded then the average of remaining numbers becomes 45. Find out the excluded numbers.
After replacing an old member by a new member, it was found that the average age of five members of a club is the same as it was 3 years ago. The difference between the ages of the replaced and the new members is
1). 2 years
2). 4 years
3). 8 years
4). 15 years