Question

From a sack of potatoes weighing 120 kg, a merchant sells portions weighing $$6 kg, 5 \dfrac{1}{4} kg, 9 \dfrac{1}{2} kg$$ and $$9 \dfrac{3}{4}$$ kg respectively.
(i) How many kg did he sell?
(ii) How many kg are still left in the sack?

Answer 1

Weight of potato $$= 120 kg$$
(i) potatoes sold by merchant $$= 6 kg + 5 \dfrac{1}{4} kg + 9 \dfrac{1}{2} kg + 9 \dfrac{3}{4} kg$$
It can be written as
$$= \left(6 + 21/4 + 19/2 + 39/4 \right)$$ kg
LCM of 1, 4 and 2 is 4
$$= \left(24 + 21 + 38 + 39 \right)/4$$
By further calculation
$$= 122/4$$
$$= 61/2 kg$$
$$= 30 \dfrac{1}{2} kg$$
(ii) Potatoes left in the sack $$= 120 kg - 30 \dfrac{1}{2} kg$$
It can be written as
$$= \left(120/1 - 61/2 \right)$$ kg
By further calculation
$$= \left(240 - 61 \right)/2$$ kg
So we get
$$= 179/2 kg$$
$$= 89 \dfrac{1}{2} kg$$