Question

if 3 Onions Weigh 0.75lb how much do 10 onions weigh

Answer 1

First find out how much one onion weighs so divide 0.75 by 3. This gets you 0.25. Now all you need to do is multiply the weight of one onion by 10, 0.25 x 10 = 2.5

Answer 2

If 3 onions weigh 0.75lb how much do 10 onions weigh?
1.) Set up a proportion
$\frac{3}{0.75} = \frac{10}{x}$
2.) Now Multiply 0.75 by 10
0.75x10= 7.5
3.) Now Divide 7.5 by 3 
7.5/3= 2.5
10 onions weigh 2.5 pounds