In a row of students, if John, who is 16th from the left, and Johnson, who is 8th from the right, interchange their positions, John becomes 33rd from left. How many students are there in the row?

According to question,
Malini is behind Anjana, but in front of Gayathri. Meena is in front of Shena, but behind Gayathri.
It is clear that , Meena is second from the last.
Standing arrangement :-

According to question,
We can draw a figure , in which Mohan is between Balu and Raju and Raju is to the immediate right of Praveen and Amith is to the right of Balu.
As shown in figure , Amith is in extreme right end .
Sitting arrangement :-

Draw a figure on the basis of above given question ,
A and B belong to Ruby House, while the rest belong to Emerald House. D and F are tall, while others are short. C and D are wearing glasses while others are not wearing.
D is from Emerald House. She is tall. She wears glasses.
sitting sequence :-

According to question,
We can draw a figure , in which D is to the right of G. C is between A and B. E is between F and D. There are three persons between G and B .
As shown in figure , G is on the extreme left .
Standing arrangement :-

Krishna is to the right of Samy.
There is no person between Samy and Krishna.
There is no person between Vaani and Sheela.
So, Saroj is sitting to the left of Samy.

According to question,
We can draw a figure , in which P is to the left of M and to the right of O. R is sitting to the right of N, but to the left of O.
From given figure it is clear that , O is sitting in the middle.
Sitting arrangement :-

According to question,
O is third from M who is standing left of N, and P is on the left of Q who is fourth from N.
As shown in figure , the position of P from right is Second .
Sitting arrangement :-

According to question,we have
Raju was shifted three places towards right
Raju's position = 3 + 8th from the right end = 11th
Total number of children = 15
? Earlier position from left = Total number of children - Raju's position + 1
Earlier position from left = 15 ? 11 + 1 = 5th

According to question,we have
Dipika's position = 11th from West
Sudesh's position = 15th from East end.
After interchanging their positions ,
Sudesh's current position = 9th from East end.
? Total number of persons in the row = Dipika's position + Sudesh's current position - 1
Total number of persons in the row = 11 + 9 ? 1
Hence ,total number of persons in the row = 20 ? 1 = 19

According to question,
We can draw a figure , in which Ankit is sitting to the immediate right of Anjum. Amit is sitting to the left of Priya and to the immediate right of Ram. Ram is sitting to the right of Ankit.
From given figure it is clear that , Priya is sitting at the extreme right end .
Sitting arrangement :-