Previous Year Questions

Building P:

There are 5 flats in each floor in building P. Number of flats in each floor is 3 less than the total number of floors.

Number of floors in building P = 5 + 3 = 8

There are ⁵√243 people in each flat in building P. So,

Number of people in each flat in building P = ⁵√243 = 3

And the total number of flats in building P = 8 * 5 = 40

Total number of people in building P = 3 * 40 = 120

Building Q:

Number of floors in building Q is 3/4 times the number of floors in building P and 5 less than the number of floors in building S.

Number of floors in building Q = 8 * 3/4 = 6

Number of floors in building S = 6 + 5 = 11

Ratio of total number of people in building P and Q is 5: 9 respectively.

Total number of people in building Q = 120 * 9/5 = 216

Building R:

Total 140 people are there in building R.

Number of flats on each floor in building R is the least prime number.

Number of flats on each floor in building R = 2

Building S:

Total √3025 flats are there in building S. Then,

Total number of flats in building S = √3025 = 55

Number of flats on each floor in building S = 55/11 = 5

Number of floors in building R is 1 less than the number of floors in building S. Then,

Number of floors in building R = 11 - 1 = 10

Total number of flats in building R = 10 * 2 = 20

And the number of people in each flat in building R = 140/20 = 7

Number of people in each flat in building R is 40% more than the number of people in each flat in building S.

Number of people in each flat in building S = 7 * 100/(100 + 40) = 5

And the total number of people in building S = 5 * 55 = 275

In tabular form:

Number of flats per floor in building Q = 2 * 7 - 5 = 9

Then, number of people per flat in building Q = 216/(6 * 9) = 4

And the number of people per flat in building S = 5

Therefore, percentage = ((5 - 4)/5) * 100 = 20%