Which of the following problems cannot be solved using a proportion?

A: A map has the scale factor 1 in = 50 miles. If the map shows the distance between Springdale and Any town to be 2.5 inches, how far apart are the two cities?

B: An 8-foot long wooden plank needs to be cut into 5-inch pieces. How many 5-inch pieces can be cut from the plank?

C:After paying $10 for one phone plan, the charge is $0.15 per minute. How much does a 20-minute phone call cost?

D: In one shop, a pound of specialty candy costs $7.99. How much will 0.75 pound of candy cost?

Question

Which of the following problems cannot be solved using a proportion? 

A: A map has the scale factor 1 in = 50 miles. If the map shows the distance between Springdale and Any town to be 2.5 inches, how far apart are the two cities? 

B: An 8-foot long wooden plank needs to be cut into 5-inch pieces. How many 5-inch pieces can be cut from the plank? 

C:After paying $10 for one phone plan, the charge is $0.15 per minute. How much does a 20-minute phone call cost? 

D: In one shop, a pound of specialty candy costs $7.99. How much will 0.75 pound of candy cost?

anonymous · Answer

B ecause the rest involve proportions

anonymous · Answer

and for every other option you're basically calculating the per something rate, and then multiplying that to get some other value. for B you can't do this, because well the question really doesn't give you anything to work with, it says oranges are orange, then asks you to calculate the oxidation state of 2d electron of oxygen under UV light. Basically the question provides no useful info, so you can't solve that with proportions.

anonymous · Answer

Thanks so much! And for explaining many people don't do that on here!