Sponsor Area

Real Numbers

Question
CBSEENMA10006145

In a morning walk Nimit, Tanvika and Mehul step off together, their steps measure 84 cm, 90 cm and 120 cm respectively. What is the minimum distance each should walk so that one can cover the distance in complete steps.

Solution

 Required distance is the LCM of 84 cm, 90 cm and 120 cm.

Thus,

Since, 84 = 2 × 2 × 3 × 7 = 22 × 3 × 7

90 = 2 × 3 × 3 × 5 = 2 × 32 × 5

and    120 = 2 × 2 × 2 × 3 × 5

= 23 × 3 × 5

∴ LCM = Product of each prime factor with highest power

= 23 × 32 × 5 × 7 = 2520

= 25 m 20 cm

Problems Based on Irrational Numbers