Step-by-step explanation:
2079 / 297 = 7
that is the first indication about what we need.
but 7 itself can't be the solution, because the solution needs to contain at least a factor of 27.
297 = 27×11
therefore,
2079 = 27×11×7
and the other number must now be
27×7 = 189
because due to the HCF it has to be divisible by 27, but must have another additional factor. a factor that allows it to divide 2079 without remainder, and makes it big enough to block any LCM lower than 2079.
there are only 2 other factors available in 2079 : 11 and 7.
297 has already "taken" 11, and the two numbers cannot be the same (otherwise the LCM and the HCF would be the number itself), so that leaves 7 for the other number.
hence the solution.
the other number is 189
and the other number must then be 27×7 = 189
