Question

What is the LCM of $2.5,0.5,0.175$?

Answer 1

Given numbers: $2.5,0.5\text{and}0.175=\frac{2500}{1000},\frac{500}{1000}\text{and}\frac{175}{1000}$
The L.C.M. of two or more fractions $=\frac{\text{L.C.M. of numerators}}{\text{H.C.F. of denominators}}$
So, LCM of $2500,500,175$:
$\Rightarrow 2500=2^2\times 5^4$
$\Rightarrow 500=2^2\times 5^3$
$\Rightarrow 175=5^2\times 7$
Since, LCM is the product of primes numbers of highest exponents.
So, LCM of numerator $=2^2\times 5^4\times 7$
As all denominator has same value, so its HCF is $1000$ itself.
Thus, LCM of given numbers $=\frac{2^2\times 5^4\times 7}{1000}$
$=17.5$