A, B, C, D and E, when arranged in descending order of their weight from top, A becomes third, E is between D and A, C and D are not at the top. Who among them is the second?

Two 9 are present which is followed by 7 and preceded by either 4 or 5.
2 3 7 8 9 1 [4 9 7] 3 6 9 8 1 5 3 [5 9 7]

The change of place by Monika can be shown as under.
1 2 3 4 5 6 7 8 9 10 11 M 13 14 15 16 17 18 19 20 21
Clearly, Monika's earlier position was 8th from the left and 14th from the right end.

Three numbers in which followed by 9 and preceded 2, 3 or 4
11 [2 3 9] 4 4 5 5 5 5 [3 3 9] 8 7 7 7 8 8 8 5 5 [4 3 9] 6 6 6 6

Clearly 1st, 8th, 15th, 22nd and 29th October are Sundays.
So, 31st October is Tuesday.
? 1st November will be Wednesday.

As per the given above figure , we can see that
The number of routes from P to Q = 2 + 4 = 6
Hence , the number of routes from P to Q is 6 .

Mohan has secured more marks than Suresh in the terminal examination. Suresh's rank is seventh from top among.
According to question,
Mohan rank will definitely better than Suresh which can be either 1, 2, 3, 4, 5, 6.

As month begins on Saturday, so 2nd, 9th, 16th, 23rd, 30th days will be Sundays. While 8th and 22nd days are second Saturdays. Thus, there are 7 holidays in all. Hence, no. of working days = 30 - 7 = 23

Clearly, the last train left two and half hours before 18.00 hrs i.e., at 15.30 hrs. But this happened 40 minutes before the announcement made. So, the announcement made at 16.10 hrs.

Nitin : 32 31 30 29 28 27 26 25 24 23 22 21 20.....................
Sumit : 1 3 5 7 9 11 13 15 17 19 21 23 25..............................
Clearly, both will never call out the same number.

Total boys = [ Mahendra 's place from left + Surendra 's place from right ] + [ Boys between them ]
= [ 17 + 18 ] + 8 = 43