You did not provide a list of expressions to select from.
Let A = area
Let w = width
Let (w + 5) = length
A = (w + 5)w
Nitrogen Radius = 5.8 x 10⁻¹¹ m
Beryllium Radius = 1.12 x 10⁻¹⁰ m
Let's find the quotient of N/Be :
(5.8x10⁻¹¹)/(1.12x10⁻¹⁰). But 10⁻¹¹/10⁻¹⁰ = 10⁽⁻¹¹⁺¹⁰⁾ = 10⁻¹ = 1/10 = 0.1
→ (5.8/1.12).(0.1) = 0.58/1.12 = 0.518.
Conclusion: the radius of Be is almost double than the radius of N
You’re trying to find the better buy so you want to find out how much you’re paying per unit (in this case kg)
So you divide the price by the unit (kg)
And find the better buy by looking at which price is cheapest.
Your answer is the 7.48 kg bag
Hope this helps and good luck!!
What do the up arrows mean? I may be able to help if you tell me.