Home › UP Board Class 10 › Mathematics › A student claims that for three positive integer…
A student claims that for three positive integers $p,q,r$, we always have $\operatorname{HCF}(p,q,r)\times \operatorname{LCM}(p,q,r)=p\times q\times r$. Which option is correct?
AThe claim is always true for any three positive integers.
BThe claim is true only when all three numbers are prime.
CThe claim is false in general for three numbers.
DThe claim is true only when two of the numbers are equal.
Answer & Solution
Correct answer: C. The claim is false in general for three numbers.
For two positive integers, $\operatorname{HCF}\times \operatorname{LCM}=\text{product of the numbers}$. But the chapter explicitly notes that this does not generally extend to three numbers. For example, for $6,72,120$, we get $\operatorname{HCF}=6$ and $\operatorname{LCM}=360$, so $6\times 360\neq 6\times 72\times 120$.
Related questions
When variables and numbers appear on both sides, you must simplify:Equations needing more than one operation are described as taking more:Once a solution is found, it should be checked by substituting it back to get a statement The product of any number and its reciprocal equals:A fraction multiplying the variable is best removed by multiplying by its:Solving x divided by 4 equals 3 gives x equal to:Solving 4x equals 20 gives x equal to:Solving x minus 8 equals 5 gives x equal to: