Question

find the least common multiple of 10 and 15 , 5 and 7​

Answer 1

Answer:

The answer is 210............

Answer 2

Answer:

10= 2x5

15= 3x5

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Since, the multiple number 5 is common in both of these, thus 5 is taken out once from them.

Now, the remaining numbers are 2 and 3. They are also taken out once.

So, LCM of 10 and 15 is 5x2x3= 30.

.

.

5= 5x1

7= 7x1

.

Since, the multiple number 1 is common in both of these, thus 1 is taken out once from them.

Now, the remaining numbers are 5 and 7. They are also taken out once.

So, LCM of 5 and 7 is 1x5x7= 35.

.

.

10= 2x5x1

15= 3x5x1

5= 5x1

7= 7x1

.

Since, the number 1 is common in all four of these. Hence, 1 is taken out eaxactly once.

Now, the number 5 is common in 10,15 and 5. So, 5 is taken out exactly once.

Now the remaining numbers are taken out, which are 2,3 and 7.

So, the LCM of 10,15,5 and 7 is 1×5×2×3×7= 210.