Find out the largest divisor for the numbers $389, 436$ and $542$ that would give $4, 7$ and $3$ respectively as remainder.

In classes $(VI, VII \text{and} VIII) 6, 7, \text{and} 8$ of a school, there are $220, 176$ and $132$ students respectively. Find the maximum number of students that can be included in a group so that the groups have equal number of students and can be made in each class.

Hamida has $527$ apples, $646$ chickoos and $748$ oranges. These fruits have to be distributed in equal heaps. What would be the number of fruits in the largest heap? How many such heaps will be formed?

A rectangular room is $122 \mathrm{m}$ long and $92 \mathrm{m}$ wide from outside. If its walls are $1 \mathrm{m}$ thick then find out the maximum length of a scale in meter that can be used to measure the inner length and width of that room.