Question
Six trophies out of which 3 are gold and the rest are
silver are to be placed in a line. Find the number of arrangements in which all three gold trophies are not placed together.Solution
Total number of ways of arrangement = 6! = 720 ways
If we consider 3 gold trophies as one item, number of arrangements among themselves = 3! = 6 ways
Number of arrangements of remaining 4 items = 4! = 24 ways
Therefore, required number of ways = 720 – (6 × 24) = 576 ways
In a seminar, the average number of male and female attendees is 540. 70% of males and 50% of females are professionals. If there are 588 non-profession...
- There are three numbers 'p', 'q' and 'r' such that average of 'p' and 'q' is 12, average of 'q' and 'r' is 28 and average of 'p' and 'r' is 20. Find the av...
The student's marks were wrongly entered as 55 instead of 25. Due to this, the average marks for the class increased by 1 /4 The number of students in t...
Ram scored an average of 5 goals per match in his first four games. However, he didn't score any goals in the following three matches. How many goals do...
- A city experienced an average rainfall of 125 cm over the first five days of a week, while the last five days recorded an average of 132 cm. If the average...
The average age of a class of 20 girls is 16 years. If 4 new girls having average age of 10 years join the class, then the average age of the class beco...
The average weight of 44 employees in an office is 45 kg. When the manager's weight is included, the average weight rises by 1 kg...
The combined average number of pens with persons ‘B’ and ‘C’ is 75% of the combined average number of pens with persons ‘A’ and ‘D’. The...
- Salaries of M, N and O are in the proportion 4:6:5. Their average salary is Rs. 18,000. If M spends 50% of salary, N spends 60%, and O spends 70%, find the...
Average of three consecutive numbers is 91. Find the sum of smallest and largest number.
