Solution:

54

It takes 3 hours for the Simpson & Stewie to meet.
so the eagle flies for 3 hours at 18 Km/hr = 54 kms

Solution:

The number is: 12345679
12345679 * 9 = 111111111
12345679 * 18 = 222222222
12345679 * 27 = 333333333
And so on...

Solution:

Let the length of the bridge be x meters.
Running towards the train, Charles covers 0.5x-10 meters in the time that the train travels x-4 meters. Running away from the train, Charles covers 0.5x+2 meters in the time that the train travels 2x-8 meters.

Because their speeds are constant, the following holds:

(0.5x-10) / (x-4) = (0.5x+2) / (2x-8)
which can be rewritten to
0.5x2 - 24x + 88 = 0
Using the abc formula we find that x=44, so the railway-bridge has a length of 44 meters.

Solution:

The riddle, the 'facts' of which may or may not be true, results in the following equation:

x/6 + x/12 + x/7 + 5 + x/2 + 4 = x

where x is Abhishek's age at the time of his death.

Therefore, salmna lived exactly 84 years.

Solution:

450

Explanation:
60 / 2(10+5) = ?
60 / 2(15) = ?
60 / 2 x 15 = ?
Using the BODMAS rule, we need to apply division first.
30 x 15 = ?
450 ..... The Answer

Solution:

4%

Explanation:
The winning chance probability is still 4% as the outcome of Samuel winning the lottery is a separate event from the 1st four losing it.

Solution:

None

The sum of numbers from 0-9(0,1,2,3,4,5,6,7,8,9) is 45 and therefore can be divisible by 3 and 9.

Solution:

12345679

12345679 × 9 = 111111111 (only 1s)
12345679 × 18 = 222222222 (only 2s)
12345679 × 27 = 333333333 (only 3s)
12345679 × 36 = 444444444 (only 4s)
12345679 × 45 = 555555555 (only 5s)

Solution:

Step 5 is invalid, because we are dividing by (x-y), and since x=y, we are thus dividing by 0. This is an invalid mathematical operation (division by 0), and so by not following basic mathematical rules

Solution:

The train is just about to leave the station and there is no way tarun will be able to catch it this time.