6th grade mathematics rates & ratios

dont answer if you dont know

which is the best buy: $4.08 for a 16-ounce box of cereal, $4.50 for an 18-ounce box of cereal, or $5.39 for a 22-ounce box of cereal?

This doesn’t make sense to me it’s supposed to be lcm ( least common multiple )

Consider the proof. given: segment ab is parallel to line de. prove: what is the missing statement in step 5?

Acompany that manufactures and sells guitars made changes in their product range. from the start they had 20 models. then they reduced the number of models to 15. as a result, the company enjoyed a 10% increase in turnover. - how much did the stock level change? in (%)