Avery special island is inhabited only by knights and knaves. knights always tell the truth, and knaves always lie.
you meet two inhabitants: ted and zippy. ted says, "of i and zippy, exactly one is a knight." zippy says that ted is a knave
can you determine who is a knight and who is a knave?

what level of math? also i don't need to be paid if i can you.

answer:   expression= p+p*d%

price reduction + sale price = $625

sale price: $p+$p*d%

where d% is the percentage of discount

step-by-step explanation:

original price = p

price went down by $150 price reduction $p*d%

sale price= $ 475

therefore the price before sale is: $625

and the expression that shows the price before sale is: p+p*d%