You could multiply 1/4 by 3 and 1/6 by 2. You would get 3/12 and 2/12. The common denomonator is 12. 4 and 6 are both multiples of 12.
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
Number 1 is proportional because if u simplify 2/24 u get 1/12
number 2 is the book palace because it goes right through the orgin , it is proportional
the answer is C. because it is the only one that does not contain a common factor :)