Correct Option (A)
The problem requires determining the least common multiple (LCM) of the step lengths to find the minimum distance each person must walk to cover the same distance in complete steps. The given step lengths are 40 cm, 42 cm, and 45 cm.
To calculate the LCM:
- Prime factorization of 40: 2³ × 5
- Prime factorization of 42: 2 × 3 × 7
- Prime factorization of 45: 3² × 5
The LCM is the product of the highest powers of all prime factors involved: 2³ × 3² × 5 × 7 = 8 × 9 × 5 × 7 = 2520 cm.
Converting 2520 cm to meters and centimeters: Since 100 cm equals 1 meter, 2520 cm is equivalent to 25 meters and 20 cm.
Therefore, the minimum distance is 25m 20cm.
Incorrect Options:
Options B (50m 40cm), C (75m 60cm), and D (100m 80cm) represent distances that are multiples of the calculated LCM (2520 cm) but are not the minimum distance required. The question explicitly asks for the minimum distance, which is precisely determined by the LCM.