# Money Math-Trick Question

• Aug 13th 2011, 01:25 PM
KayPee
Money Math-Trick Question
Kane has $50.00. He goes to the supermarket and buys football boots and then he buys a soccer ball, which is half the price of the football boots.He then spends half of what she has left on a belt, leaving him with$15.00.

How much did the soccer ball cost?

How much did the football boots cost?

I started it like this:

Let x= price of football boots

Let 1/2(x) = price of soccer ball

the combined cost of soccer ball and football boots = x + 1/2(x)

Amount spent on the football boots and soccer ball :

$50-( I am stuck The text gives a clue that the price of the belt =$15
(How did they arrive at the conclusion that the price of the belt equals $15?) Anyone has any ideas as to how I can move on? Thanks • Aug 13th 2011, 01:40 PM anonimnystefy Re: Money Math-Trick Question let y be the amount of money after he buys both football and soccer boots.then the price of the belt is 1/y.after buying the belt he has$15.so the equation is:
y-y/2=$15 can you solve it from here? • Aug 13th 2011, 03:09 PM e^(i*pi) Re: Money Math-Trick Question Quote: Originally Posted by KayPee Kane has$50.00. He goes to the supermarket and buys football boots and then he buys a soccer ball, which is half the price of the football boots.He then spends half of what she has left on a belt, leaving him with $15.00. How much did the soccer ball cost? How much did the football boots cost? I started it like this: Let x= price of football boots Let 1/2(x) = price of soccer ball the combined cost of soccer ball and football boots = x + 1/2(x) Amount spent on the football boots and soccer ball :$50-(

I am stuck

The text gives a clue that the price of the belt = $15 (How did they arrive at the conclusion that the price of the belt equals$15?)

Anyone has any ideas as to how I can move on?

Thanks

Let x be the price of the boots

After buying the football and the football boots he is left with: $y = \left[50 - \left(x+ \dfrac{x}{2}\right)\right]$

He then spends half of this on the belt and is left with $15: $y - \dfrac{y}{2} = 15$ Of course we have an expression for y in x so sub that in: $\left[50 - \left(x+ \dfrac{x}{2}\right)\right] - \dfrac{1}{2}\left[50 - \left(x+ \dfrac{x}{2}\right)\right] = 15$ And after simplification: $\left(50 - \dfrac{3x}{2}\right) - \left(25 - \dfrac{3x}{4}\right) = 15$ Solve for x, which is the price of the boots • Aug 14th 2011, 06:45 AM HallsofIvy Re: Money Math-Trick Question Quote: Originally Posted by KayPee Kane has$50.00. He goes to the supermarket and buys football boots and then he buys a soccer ball, which is half the price of the football boots.He then spends half of what she has left on a belt, leaving him with $15.00. Well, you said this was a trick question! Who is "she" and how much money does she have? Quote: How much did the soccer ball cost? How much did the football boots cost? I started it like this: Let x= price of football boots Let 1/2(x) = price of soccer ball the combined cost of soccer ball and football boots = x + 1/2(x) Amount spent on the football boots and soccer ball :$50-(

I am stuck

The text gives a clue that the price of the belt = $15 (How did they arrive at the conclusion that the price of the belt equals$15?)

Anyone has any ideas as to how I can move on?

Thanks
You were told that he spent "half of what [s]he has left on a belt" and then had $15 left. If you spend "half", you have "half" left. That means that before buying the belt, he had$30. That means that the boots and ball cost 50- 30= \$20. Taking x to be the cost of the boots, the ball cost x/2 so x+ x/2= 3x/2= 20.