Question
The average number of novels on historical, thriller and
fantasy in a library is 120, and the average number of novels on historical and fantasy is 110. If the number novels on fantasy is 15% less than the number of novels on thriller, then what is the number of novels on historical in the library?Solution
Let the number of novels on historical, thriller and fantasy be x, y and z respectively. Given, (x + y + z)/3 = 120 => x + y + z = 360 ….. (1) And, (x + z)/2 = 110 => x + z = 220 ….. (2) From equation 1 and 2 Number of novels on thriller = y = 140 Number of novels on fantasy = 0.85 × 140 = 119 Therefore, number of novels on historical = 360 – (140 + 119) = 101
There are three categories of jobs HR, CA and PA. The average salary of the student who got the job of HR and CA category is 20 lakhs per annum. The ave...
A and B started a business investing Rs. 1500 for ‘x’ months and Rs. 1800 for 10 months, respectively. Out of total profit of Rs. 5000, profit shar...
Four numbers are arranged in ascending order. When the first two numbers are increased by the number equal to their position, and the last two numbers i...
The average of a set of 's' numbers is 50. If 120 is added to the set, then the average of the set becomes 50.4. Find the value of '4 X (s - 20)'.
 A hollow spherical metallic ball has an external diameter 8cm and is 1/2cm thick. The volume of the ball (in cm cube) is.
The average weight of 4 persons is 40 kg. The heaviest person’s weight is 26 kg more than the lightest person’s weight. If the average weight of the...
The average salary of a group of 12 employees is Rs. 60,000. When one employee departs, the average salary of the remaining 11 employees drops by Rs. 2,...
While tabulation of marks scored in an examination by the students of a class, by mistake the marks scored by one student got recorded as 93 in place o...
The average of 18 numbers is 28. The average of first 10 numbers is 30 and that of the last 10 numbers is 26. If 9th number and 10th numbers are exclud...
Average of five two-digit consecutive even natural numbers is (m + 9), and the average of five two-digit consecutive odd natural numbers is (n - 6). Whe...
