Question
Which of the following gas usually causes explosions in
coal-mines?Solution
Methane explosions occur in coal-mines when a buildup of methane gas, a by-product of coal, comes into contact with a heat source, and there is not enough air to dilute the gas to levels below its explosion point.
- The average of 25, 39, 56, 44, 31, and 'x' is 41. What is the value of 'x²'?
In a class of 50 students, the girls are 76%. The average weight of boys is 62 kg and that of girls is 58 kg. What is the average weight (in kg) of whol...
The number of students in class 'A' is 140, and the ratio of girls to boys is 9:5. If the average number of boys in classes A and B is 160, and the aver...
The average of 10 numbers is 102. The average of the first 5 numbers is 78 and the average of the last 4 numbers is 46. What is the 6th number?
Find the average of the following sets of numbers.
693, 456, 876, 532, 934, 691, 596, 398, 682
There are two sections A and B of a class, consisting of 38 and 42 students, respectively. If the average weight of the students of section A is 55 kg a...
Average present age of 'A', 'B' and 'C' is 25 years whereas average present age of 'A', 'B', 'C' and 'D' is 27 years. Three years hence from now, ratio ...
Average marks scored by each boy in a class were 75, whereas that by each girl were 85. If the number of boys is 50% more than the number of girls, then...
The average of two consecutive even numbers is 61. If the smaller number is increased by 18% and the larger number is decreased by 18%, then find the di...
The average age of a group of persons going for tour to Shimla is 22 years. 30 new persons with an average age of 8 years join the group and their avera...
Relevant for Exams:
