All Exams Test series for 1 year @ ₹349 only
Question

A floor of a big hall has dimensions 30 m 60 cm and 23 m 40 cm. It is to be paved with square tiles of same size. What is the minimum number of tiles required ?

This question was previously asked in
CDS I 2023 English Previous Year Paper (16-April-2023)
The correct answer is

221

Calculating Minimum Tiles for the Hall Floor

The problem asks for the minimum number of identical square tiles needed to pave a large hall floor. The hall has dimensions 30 m 60 cm by 23 m 40 cm. To find the minimum number of tiles, we need to use the largest possible square tile size that can fit perfectly into the floor dimensions.

1. Convert Hall Dimensions to a Single Unit

First, let's convert the hall's dimensions into a single, consistent unit, preferably centimeters (cm), to simplify calculations.

  • Length of the hall = 30 m 60 cm
  • Since 1 meter = 100 cm, 30 meters = \(30 \times 100 = 3000\) cm.
  • Total Length = \(3000 \text{ cm} + 60 \text{ cm} = 3060 \text{ cm}\).
  • Width of the hall = 23 m 40 cm
  • Since 1 meter = 100 cm, 23 meters = \(23 \times 100 = 2300\) cm.
  • Total Width = \(2300 \text{ cm} + 40 \text{ cm} = 2340 \text{ cm}\).

So, the dimensions of the hall floor are 3060 cm by 2340 cm.

2. Determine the Largest Possible Square Tile Size

To use the minimum number of tiles, the size of each square tile must be maximized. The side length of the square tile must perfectly divide both the length (3060 cm) and the width (2340 cm) of the hall floor without any remainder. Therefore, the side length of the largest possible square tile is the Greatest Common Divisor (GCD) of 3060 and 2340.

3. Calculate the GCD of the Dimensions

We can find the GCD using the Euclidean algorithm:

  1. Divide 3060 by 2340: \(3060 = 1 \times 2340 + 720\)
  2. Divide 2340 by the remainder 720: \(2340 = 3 \times 720 + 180\)
  3. Divide 720 by the remainder 180: \(720 = 4 \times 180 + 0\)

The last non-zero remainder is 180. Thus, the GCD(3060, 2340) = 180 cm.

This means the largest possible square tile that can pave the floor has a side length of 180 cm.

4. Calculate the Number of Tiles Required

Now, we calculate how many tiles fit along the length and width of the hall.

  • Number of tiles along the length = \(\frac{\text{Length of hall}}{\text{Side of tile}} = \frac{3060 \text{ cm}}{180 \text{ cm}}\)
  • Number of tiles along the length = \(17\)
  • Number of tiles along the width = \(\frac{\text{Width of hall}}{\text{Side of tile}} = \frac{2340 \text{ cm}}{180 \text{ cm}}\)
  • Number of tiles along the width = \(13\)

The total minimum number of tiles required is the product of the number of tiles along the length and the number of tiles along the width.

  • Total tiles = (Number of tiles along length) \(\times\) (Number of tiles along width)
  • Total tiles = \(17 \times 13\)
  • Total tiles = \(221\)

Conclusion

Therefore, the minimum number of square tiles required to pave the hall floor is 221.

Was this answer helpful?

Similar Questions

  1. If (x + k) is the HCF of x 2+ px + q and x 2+ qx + p, where p ≠ q, then what is the value of k ?

  2. If (x + k) is the HCF of x 2+ 5x + 6 and x 2+ 8x + 15, then what is the value of k?

  3. Let L be the LCM and H be the HCF of two given numbers. L and H are in the ratio 3 ∶ 2. If the sum of the two numbers is 45, then what is the product of the numbers?

  4. The sum of LCM and HCF of two numbers is 1484 and the difference between LCM and HCF is. 1428. If one of the numbers is 112, then what is the other number?

  5. The LCM of two prime numbers p and q is 2231, where p > q. What is the value of p - q ?

  6. What is the HCF of (x8– y8) and (x7– y7+ x5y2– x2y5) ? 

  7. Three runners are running in a circular track, and they complete one round in 20, 30 and 35 minutes respectively. When will they next meet at the starting point ?

  8. What is the least perfect square which is divisible by 3, 4, 5, 6 and 7?

  9. If (x - k) is the HCF of x 2+ ax + b and x 2+ cx + d, then what is the value of k?

  10. If x is the HCF and y is the LCM of \(\frac{3}{5}, \frac{6}{25}, \frac{9}{20}, \frac{27}{50},\)  then which one of the  following is correct?


Important Questions from LCM and HCF

  1. The HCF and LCM of two numbers are 12 and 72, respectively. If the ratio of the two numbers is 2 ∶ 3, then the larger of the two numbers is:

  2. Find the greatest number that will divide 43, 91 and 183 so as to leave the same remainder in each case.

  3. Joseph visits the club on every 5 th day, Harsh visits on every 24 th day, while Sumit visits on every 9 th day. If all three of them met at the club on a Sunday, then on which day will all three of them meet again?

  4. The sum of two numbers is 1215 and their HCF is 81. How many such pairs of numbers can be formed?

  5. The LCM of two numbers in 48. Their ratio is 2:3 What is the sum of the numbers?

Need Expert Advice?
Upcoming Exams
NDA
September 13, 2026
CDS
September 13, 2026
Test Series
CDS img
Defence
UPSC CDS 2026 Mock Test Series
540 Tests 4 Tests Free
1363 Attempts
4.3(172)
English, Hindi
More Questions from CDS

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App