Percentage and Average

In a class of 52 students the number of boys is two less than the number of girls. Average weight of the boys is 42 kg, while the average weight of all the 52 students is 40 kg. Approximately, what is the average weight of the girls?

• 37 kg

• 38 kg

• 39 kg

• 39.5

The average weight of 8 persons increases by 1.5 kg when a person weighing 65 kg is replaced by a new person, what could be the weight of new person?

• 76 kg

• 77 kg

• 76.5 kg

• 77.5 kg

In an examination, a candidate obtains 25% marks and fails by 45 marks while another candidate obtains 46% marks and passes by 15% marks more of those required for passing. What are the passing marks?

• 120

• 40

• 80

• 125

20 pages were to be copied on all. I copied 5 and my friend copied 15. What percent of my friend's work did I do?

• 25%

• 30%

• 5/20 %

• none of these

A mathematics teacher tabulated the marks secured by 35 students of 8th class. The average of their marks was 72. If the marks secured by Reema was written as 36 instead of 86 then find the correct average marks upto two decimal places.

• 73.41

• 72.43

• 73.43

• 74.31

The arithmetic mean of the scores of a group of students is 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:

• 54.6%

• 57%

• 50%

• 51.4%

A batsman in his 20th innings makes a score of 110 and thereby increases his average by 4. What is his average after 20 innings?

• 30

• 34

• 38

• 43

10% of 15% of 20% of Rs. 500 is:

• Rs. 25

• Rs. 15

• Rs. 150

• Rs. 1.50

Sugar is now being sold at Rs. 15 per kg. During last month its rate was Rs. 13 per kg. Find by how much percent must a family reduce its consumption to keep the expenditure fixred?

• 13 1/3%

• 14%

• 15%

• 15 1/5%

The average price of 10 books is Rs. 12 while the average price of 8 of these books is Rs. 11.75. Of the remaining two books, if the price of one is 60% more than the price of the other, what is the price of each of these two books?

• Rs. 8; Rs. 12

• Rs. 10: Rs. 16

• Rs. 6: Rs. 7.5

• Rs. 12: Rs. 14