Question

how do i know whether i have to find lcm or hcf in the above sum

Answer 1

you have to buy pencils or crayons in full of packs and not loosely .

each of pencil pack is of 24
and
each of crayon pack is of 32

so pencils are multiple of 24
and
crayons are multiple of 32

but both must be same

it means we have to take their l.c.m.

24 = 2 × 2 × 2 × 3

32 = 2 × 2 × 2 × 2 × 2


lcm = 2 × 2 × 2 × 2 × 2 × 3

lcm = 96

so we can buy 96 of each pencils and crayons

I.e. 24 × 4 packs of pencils

and 32 × 3 packs of crayons