Question

Which is a better by 3 lb of pears for $3.87 or 5 lb of pears for $6.65

Answer 1

Since 3lb pears is $3.87 lets say that every 1lb of pears costs $1.30.
say if you were to buy 2lb on-top of the 3lb it would cost $2.60 extra, causing the total price to be around $6.50 (rounded up)

so since 5lb is $6.65, i believe that the 3lb of pears is the better buy. 

Answer 2

For the first option:
If you can buy 3 lb of pears for $3.87 then you can buy 1 lb of pears for 3.87÷3=$1.29

Forbthe second option:
If you can buy 5 lb of pears for $6.65 then you can buy 1 lb of pears for 6.65÷5=$1.33

As we can see, it is cheaper to buy from the first seller as 1 lb of pears is 4 cents cheaper to buy than the second option. So, 3 lb of pears for $3.87 is a better buy.