In a row of people all facing North, Zoha is 25th from the right end. Piya is…

Concept. In a single straight row, the two ways of locating one person are tied together by a single identity: if a person stands p-th from the left end and q-th from the right end, the row holds p + q − 1 people, because the two counts cover the whole row but overlap on that one person.

Concept. Saying that one person stands exactly between two others means that person is the midpoint of the pair: the number of places from the first person to the middle one equals the number of places from the middle one to the second, so an identical gap repeats on either side of the middle person.

Application.

1. Measure everything from one fixed end. Counting from the right end, Zoha stands 25th and Piya stands 34th.

2. The gap between them is 34 − 25 = 9 places, and Piya lies farther from the right end than Zoha does.

3. Piya is the midpoint of Zoha and Minal, so that same 9-place gap repeats on Piya's other side: Minal stands 34 + 9 = 43rd from the right end.

4. Minal is also given as 6th from the left end. Applying the identity with p = 6 and q = 43 gives the total = 6 + 43 − 1 = 48.

Cross-check.

• Reading the row backwards: in a line of 48, a person 6th from the left stands 48 − 6 + 1 = 43rd from the right, which is exactly where the midpoint step placed Minal.

• Converting all three to left-end counts in a row of 48: Minal is 6th, Piya is 48 − 34 + 1 = 15th, and Zoha is 48 − 25 + 1 = 24th. The midpoint of 6 and 24 is (6 + 24) ÷ 2 = 15, so Piya does sit exactly between Minal and Zoha.

• The side matters: Minal has to lie beyond Piya, away from Zoha. Had Minal stood on Zoha's side of the row instead, Piya could not have been between the two at all, so the arrangement is forced.

The row therefore holds 48 people.