Total target cost for 5 items = 5 * 40 = 200. Cost of the first four items = 30 + 35 + 45 + 50 = 160. Cost of the 5th item = 200 - 160 = Rs. 40.
7543
The average age of 11 cricket players is 20 years. If the age of the coach is also included, the average age increases by 10%. The age of the coach is:
Current average = 20 years. Total age of 11 players = 11 * 20 = 220 years. A 10% increase in average means the new average is 20 + 2 = 22 years. With the coach, there are 12 people. Total age = 12 * 22 = 264 years. Coach's age = 264 - 220 = 44 years.
7544
The average salary of 20 male employees is Rs. 15,000 and that of 30 female employees is Rs. 10,000. What is the average salary of all employees?
Total salary of males = 20 * 15,000 = 300,000. Total salary of females = 30 * 10,000 = 300,000. Total salary of all 50 employees = 300,000 + 300,000 = 600,000. Average salary = 600,000 / 50 = Rs. 12,000.
7545
In a family of 5 members, the average age at present is 33 years. The youngest member is 9 years old. The average age of the family just before the birth of the youngest member was:
Present total age of 5 members = 5 * 33 = 165 years. 9 years ago (just before the youngest was born), the total age of the remaining 4 members was 165 - (5 * 9) = 165 - 45 = 120 years. Their average age then = 120 / 4 = 30 years.
7546
The average of 5 quantities is 6. The average of 3 of them is 8. What is the average of the remaining two numbers?
Total increase in the sum = 2 + 4 + 6 + 8 + 10 = 30. The average increase is the total increase divided by the number of items: 30 / 5 = 6. The new average is 14 + 6 = 20.
7549
A shopkeeper's average daily profit for the first 15 days of a month is Rs. 250, and for the next 15 days is Rs. 300. What is his average daily profit for the 30 days?
Total profit for first 15 days = 15 * 250 = 3750. Total profit for next 15 days = 15 * 300 = 4500. Total for 30 days = 3750 + 4500 = 8250. Average = 8250 / 30 = 275. Alternatively, since the number of days is equal (15 and 15), simply average the two averages: (250 + 300) / 2 = 275.
The odd numbers up to 100 are 1, 3, 5, ..., 99. The average of an arithmetic progression is (first term + last term) / 2 = (1 + 99) / 2 = 100 / 2 = 50.
