Fifteen children are standing in a row facing north. Ravi is to the immediate left of Prabha and is eighth from the left end. Arjun is second from the right end. Which of the following statements is not true?

Let us assume the number of boys in school be B.
Then number of girls in school = 2B
According to question,
B + 2B = 180
3B = 180
B = 180/3 = 60
Number of boys = 60
Number of girls = 120
Rupesh (a boy) ranked 34^th from top and 18 girls are ahead of Rupesh.
Number of boys after the rank of Rupesh = 60 ? 16 = 44

The specified digits are 8, 2 and 9. Now, we know a perfect square number does not have 8 and 2 at unit's place. Therefore, we can make only two three-digit numbers from it, i.e., 829 and 289. Among these two numbers, 289 is a perfect square number, i.e., square of 17. Thus, unit's digit is 7 and ten's digit is 1.

Four times 3 present together with 2 and 7, where 2 and 7 present either side of 3.
1 1 1 1 3 3 2 2 [2 3 7] 7 3 3 3 6 6 4 [7 3 2] 4 9 8 7 [7 3 2] 3 3 3 4 4 [2 3 7]

If the day before yesterday was Saturday, then today is Monday.
Thus, tomorrow will be Tuesday and day after tomorrow will be Wednesday.

Given that :- 1st March is Saturday.
Other Saturdays in March = 8, 15, 22, 29
Therefore, 1st April = Saturday + 3 days = Tuesday

According to the question,
Rajnish is older than Rajesh and Raman.
Rajnish > Rajesh, Raman..........(i)
Ramesh is older than Rajesh but younger than Rajeev.
Rajeev > Ramesh > Rajesh........(ii)
Raman is older than Rajeev.
Raman >Rajeev.......................(iii)
Combining all, we get
Rajinish > Raman > Rajeev > Ramesh > Rajesh

According to question,
If the positions of the first and the fifth digits of the number 83721569 are interchanged.
After interchange the new number = 13728569
similarly, the positions of the second and the sixth digits are interchanged.
Again after interchange the new number = 15728369

New arrangement of numbers is as follows: 15728369
Hence, third number from right end is 3.

According to question,
In a row of boys Akash is fifth from the left
Left 1 - 2 - 3 - 4 - Akash - 6 - 7 - 8 - 9 - 10 - 11 - 12 .................................................................................................................. Right
If Akash is twenty-fifth from the right then
Left 1 - 2 - 3 - 4 - Akash - 6 - 7 - 8 - 9 - 10 - 11 - 12 - 13 -14 - 15 -16 -17 -18 -19 - 20- 21- 22 - 23- 24- 25 -26 -27 -28 - 29 Right
Nikhil is eleventh from the right.
Left 1 - 2-3 -4 - Akash - 6 -7- 8- 9-10 -11-12- 13-14- 15 -16-17-18 - Nikhil -20-21-22 - 23 - 24 - 25-26 -27- 28- 29 Right

There are (25 ? 11? 1) = 13 boys between Akash and Nikhil.

According to given question,
If the positions of the first and the sixth digits of the group of digits 3 5 9 7 2 8 0 1 6 4 are interchanged.
New number after interchange = 8 5 9 7 2 3 0 1 6 4
Then the positions of the second and the seventh digits are interchanged.
New number after interchange = 8 0 9 7 2 3 5 1 6 4

After interchanging the number becomes as follows: 8 0 9 7 2 3 5 1 6 4

fourth digit from the right end after the rearrangement : 5

Total students = [ First position of Ganesh + Second position of Rajan ] ?1
Total students = [12 + 20] ? 1 = 31