A shop sold 5 types of items over a week: 120, 150, 110, 130, and 140 units respectively. After receiving a return of 10 units from the first item, what is the new arithmetic mean (in units) of items sold?
128
First, add the units of the five items as originally sold: \(120 + 150 + 110 + 130 + 140 = 650\) units.
A return of 10 units comes from the first item, so this quantity is subtracted from the total sold: \(650 - 10 = 640\) units.
The number of item types remains 5, so divide the adjusted total by 5 to get the new mean: \(\frac{640}{5} = 128\).
Hence, the new arithmetic mean of items sold is 128 units.
The average of 28 numbers is 77. The average of first 14 numbers is 74 and the average of last 15 numbers is 84. If the 14 th number is excluded, then what is the average of remaining numbers? (correct to one decimal places)
24 students collected money for donation. The average contribution was Rs. 50. Later on, their teacher also contributed some money. Now the average contribution is Rs. 56. The teacher’s contribution is:
Out of 6 numbers, the sum of the first 5 numbers is 7 times the 6 th number. If their average is 136, then the 6 th number is:
The average of five numbers is 30. If one number is excluded, then average becomes 31. What is the excluded number?
The average weight of 49 students in a class is 39 kg. Seven of them whose average weight is 40 kg leave the class and other seven students whose average weight is 54 kg join the class. What is the new average weight (in kg) of the class?