Question

three children step off together for the morning walk. Their steps measure 20cm,25cm and 30cm respectively.At what distance from their start will the three children step together again??​

Answer 1

Answer :

They will step off together again at a distance of 300 cm.

Step-by-step explanation :

Given that :

3 children step off together for the morning walk.

Their steps measure:

• 20cm
• 25cm
• 30cm

To Find :

Distance from their start will the three children step together again.

Solution :

We have to find LCM of given values.

• 20cm
• 25cm
• 30cm

So,

★ 20 :

$\begin{array}{r|l} 2 & 20 \\ \cline{1-2} 2 & 10 \\\cline{1-2} 5 & 5 \\\cline{1-2} & 1 \end{array}$

★ 25 :

$\begin{array}{r|l} 5 & 25 \\\cline{1-2} 5 & 5 \\\cline{1-2} & 1 \end{array}$

★ 30 :

$\begin{array}{r|l} 2 & 30 \\\cline{1-2} 3 & 15 \\\cline{1-2}5 & 5 \\\cline{1-2}&1\end{array}$

Now, Write their factors together,

★ 20 = 2✔️ × 2 × 5 ✔️

★ 25 = 5✔️ × 5✔️

★ 30 = 2✔️ × 3 × 5 ✔️

___________________

LCM = 2 × 2 × 5 × 5 × 3 = 300

∴ They will step off together again at a distance of 300 cm.

Answer 2

Answer:

300 cm

Step-by-step explanation:

Dear student,

let's first try to figure out the concept behind it

When we have three numbers, they can have a common multiple.

Which means, they repeat themselves at the same values but at different time intervals

the concept behind this is that multiplication is repetetive addition.

Now, we can use this concept to proceed for the answer to our question

according to the question, the three step distances of three children are-

20

25

30

now, as it is asked that after what distance, they would start to step together

so, we have to find the LCM of the three numbers

the LCM of 20, 25 and 30 will be 300

this gives the answer as-

After 300 cm, the children would step together again