Answer:
20 Kg
Explanation:
let b represent the weight of 1 bag of sand
after using
of 1 bag there is
bag left along with the unused bag , then
b + b = 35 ( multiply through by 4 to clear the fraction )
3b + 4b = 140
7b = 140 ( divide both sides by 7 )
b = 20
that is one full bag weighs 20 Kg