Exams

True, Air is a Mixture.

Air is considered as mixture for the following reasons ;

1. Air can be separated into its components like N2, O2 , Argon and CO2 by the process of fractional distillation of liquid air.

2. Air shows the properties of all the gases present in the atmosphere.
For example : Oxygen is good Supporter of combustion. Hence air also is good supporter of combustion.

3. Air does not have a fixed formula.

4. Air has a variable composition because air at different places contains different amount of gases.

5. Heat or Light energy is neither absorbed nor released when air is prepared physical by mixing required amount of gases .

6. Mixture does have fixed boiling Point. It holds good in case of liquid air.

The statement mentions that chances of heart ailments are greatly reduced by a regular half-hour exercise. So, a follows. However, it talks of only reducing the probability which does not mean that persons involved in sedentary jobs shall definitely suffer from heart ailments. So, b does not follow.

Hence, concusion a only follows the given statement.

Let their ages be x, y, z
Hence given that x + y + z = 65
Now, six years ago x age is x - 6, y is y - 6 and that of z is z - 6
Then the sum of their ages six years ago is (x + y + z) - (6 + 6 + 6) = 65 - 18 = 47

Half the Product of Number in the upper & lower box gives the number in the middle box.

i.e. 18 x 4/2 = 36

15 x 6/2 = 45

In the same way 

8 x N/2 = 44 => N = 11.

Slant surface of a pyramid=1/2 perimeter of base slantheight

=1/2 x (4  x Side of squarebase) x Slantheight

First ten odd numbers form an arithmetic progression of the form
1,3,5,7,9......
here a = first term = 1
d = common difference = 2
Average of first n numbers = (2a + (n - 1)d)/2
n th term of the AP = a + (n - 1)d
Substituting a = 1, d = 2 and n = 10 in the above formulas
average of first 10 numbers = 10
10 th term of the AP = 19
Therefore average of first 10 terms is 19 - 10 = 9 greater than
the last term. Hence the average is greater than the sum by
9/19 X 100 = 900/19 %

Since half of the four children are girls, two must be boys. It is not clear which children have blue or brown eyes. So only statement (b) follows.

• A 360-foot-high (110 metres) flag post, said to be the country's tallest, was inaugurated at the Indo-Pak Attari Border, just a stone's throw from Pakistan.
• Punjab Minister Anil Joshi inaugurated the country's largest tricolour on the tallest flag post - measuring 110 metres in length, 24 metres in width and 55 tons in weight. Built at an approximate cost of Rs 3.50 crore, the post was a project of the Amritsar Improvement Trust Authority of the Punjab Government.