The LCM of the numbers 2.1 and 0.68 is:

Correct option is A

Given:

Numbers: 2.1 and 0.68

Formula Used:

If a=$$\frac{p_1}{q_1},\ b=\frac{p_2}{q_2}$$​​

​$$\text{LCM}(a,b)=\frac{\text{LCM}(p_1,p_2)}{\gcd(q_1,q_2)}$$​​

Solution:

​$$2.1=\dfrac{21}{10}$$​​

​$$0.68=\dfrac{68}{100}=\dfrac{17}{25}$$​​

Now,
$$\text{LCM}(21,17)=21\times 17=357 \quad (\text{since }17\text{ is prime and coprime to }21)$$​​
gcd(10 ,25) = 5
$$\text{LCM}=\frac{357}{5}=71.4$$​