percentage problem

[jalshri]

A dealer buys a boat at auction and pays 10% below list price. He then sells the boat at a profit of 30% of his cost of the boat. At the same selling price, what would the dealer's percent profit over his cost have been if he had bought the boat at list price?
ans: 17

[nareshchowdary28]

Hi Jalshri,

As they mentioned just take the advantage of smart numbers when deal with percentages.

Consider original list price - 100
Dealer buys at 10% less - 90
Dealer sold it for profit of 30% = 30%(90) = 27
Dealer sold amount = 90+27 = 117

But the profit percent if you would've bought the boat at listed price = 117 - 100 = 17

Hope that helps.

[vikasapkal]

A dealer buys a boat at auction and pays 10% below list price. He then sells the boat at a profit of 30% of his cost of the boat. At the same selling price, what would the dealer's percent profit over his cost have been if he had bought the boat at list price?
ans: 17

Final answer asked in percent -

Let the list price - 100 dollars

cost at auction = .9*100
= 90 dollar

selling price = 1.30*90
= 117 dollars

here is the trick what i feel (if he had bought the boat at list price)
profit = selling price - cost at listed price
= 117-100
=17
final answer asked in percentage ,

so p percent of x is y then
(p/100) x= y

hence,
(p/100) * 100 = 17

hence percent profit (p) = 17%

vikas

[tommywallach]

Great explanations all. You should absolutely use smart numbers when you see PERCENTS or FRACTIONS (or VARIABLES). Don't be attached to the idea of using algebra every time. Good test takers always plug in. It's easier!

-t