Question

Calculate how much each size per gram, and circle which gives the best value for money. 250g for $2.30, 400g for &3.40, 1Kg for $5.65

Answer 1

To do this, we must set up ratios:
Option One:
$\frac{2.30}{250g} \\ \frac{0.0092}{1g} \\ 0.0092/g$
The first options costs only $0.0092/gram (a fraction of a penny)!
Option Two:
$\frac{3.40}{400g} \\ \frac{0.0085}{1g} \\ 0.0085/g$
The second option costs only $0.0085/gram (cheaper than option one)!
Option Three: 
This requires a little more work. First, we have to convert the grams into kilograms. For every 1 kg, there is 1,000 g. Therefore, 1,000g costs $5.65. Next, we set up the ratio as usual:
$\frac{5.65}{1000g} \\ \frac{0.00565}{1g} \\ 0.00565/g$
The third option costs $0.00565/gram.

Therefore, option three is the cheapest! 

Hope this helps!