Mandy finds she can get a discount on corn cobs if she buys in bulk. She can get 100 kilograms of corn cobs for $160 from Matt, on condition that she buys at least 100 kilograms. From another supplier, Robert, she can buy small quantities of corn cobs (100 or less) for $1 per cob or larger quantities (more than 100) for $0.60 per cob. Mandy charges all of her customers by weight, so she gets $5 per kilogram of corn cobs or $1.25 for an individual corn cob. If Mandy is going to sell over 100 kilograms of corn cobs today, what is the best profit per corn cob she can make? Answer: 85 cents

Can Rainy pls answer this, because your explanations are really good 🙂

1 answer

Just got in and saw your question. You should not direct a question at a
specific tutor, since that often results in other tutors ignoring the question.

The wording is a bit confusing to me. You are talking about bying and selling
corn by the kg and then by the individual cob. You don't say how many cobs
are in 1 kg of corn, but from "she gets $5 per kilogram of corn cobs or $1.25 for an individual corn cob", I will conclude that there are 4 cobs/kg . (5.00/1.25 = 4)
You also say that she sells over 100 kg of corn, so obviously she must have
bought over 100 kg of corn
let the number of cobs of corn bought and sold be 400+x , ..... (4(100 kg) + x )

Supplier Matt:
cost price = 160/400 = $0.40 per cob
cost of the 400+x cobs = .4(400+x) = 160+.4x
selling price = 1.25(400+x) = 500+1.25x
profit = 500+1.25 - 160 - .4x = 340 + .85x

supplier Robert: Since Mandy buys and sells more than 100 kg, his minimum
cost formulas does not apply and we will go with the cost price of 60 cents per cob
cost price = .6(400+x) = 240 + .6x
selling price = same as above = 500+1.25x
profit = 500+1.25x - 240 - .6x = 260 + .65x

So clearly, it all depends on how many cobs of corn above the 400 cobs Mandy buys and sells.
I must be missing something or else mis-interpreting the question.