Question

A pile of sand has a weight of 90kg the sand is put into a small bag and a medium bag and a large bag in the ratio 2:3:7

Answer 1

90kg of sand had been puted in 3 bags but in 2+3+7=12 parts.
90kg/12=7.5kg
Small bag has 2 parts which is 7.5kg*2=15kg
Medium bag has 3 parts which is 7.5kg*3=22.5kg
Large bag has 7 parts which is 7.5kg*7=52.5kg
2:3:7=15kg:22.5kg:52.5kg
15kg+22.5kg+52.5kg=90kg