Posers and Puzzles
12 May 12
12 May 12
Five guys have had a party in the desert, and take a taxi to get home. They agree that each of the four pays a share of the cab fare that reflects the costs that are caused by taking him home, as is, after all, fair. Calling the cab in the first place costs $8, and there is an extra $1 per mile.
From the party place at (0,0) the taxi drives
* drop Andrew off at (3,4)
* drop Bob off at (6,0)
* drop Chuck off at (9,0)
* drop Dan off at (9,4)
Ed doesn't need to get into the taxi at all, as this time the party was at Ed's home.
The total cost is $8 + $5 + $5 + $3 + $4 = $25.
How much should everyone pay for the cab fair?
20 May 12
Originally posted by talzamirThis is similar to the restaurant conundrum:
Five guys have had a party in the desert, and take a taxi to get home. They agree that each of the four pays a share of the cab fare that reflects the costs that are caused by taking him home, as is, after all, fair. Calling the cab in the first place costs $8, and there is an extra $1 per mile.
From the party place at (0,0) the taxi drives
* drop Andre ...[text shortened]... total cost is $8 + $5 + $5 + $3 + $4 = $25.
How much should everyone pay for the cab fair?
Three customers go to a restaurant and have a meal. The bill comes to £25. They each a give a £10 note to the waiter. He can't work out how much change to give back to each customer, so he keeps £2 tip and gives £1 back to each customer.
So the customers have paid £9 each, (£27), the waiter has £2. Where is the missing £1?
20 May 12
1 edit
Originally posted by talzamirThat's true. I would give A, B, C, and D a weight equal to the total costs minus the costs they would've had without that person. So for A it would be $25 - ($8 + $6 + $3 + $4) = $25 - $21 = 4
oops! ^^ Sorry about that. A nice problem anyhow. I thought of it again when thinking of the Roman inheritance, as they both look simple enough on top but it is hard to justify one answer to be the only correct one.
21 May 12
Originally posted by Pianoman1Surprisingly hard to see how people think about this the wrong way.
This is similar to the restaurant conundrum:
Three customers go to a restaurant and have a meal. The bill comes to £25. They each a give a £10 note to the waiter. He can't work out how much change to give back to each customer, so he keeps £2 tip and gives £1 back to each customer.
So the customers have paid £9 each, (£27), the waiter has £2. Where is the missing £1?
The customers each paid $9 x 3 = $27: true
The waiter has $2: true
The waiter's $2 is separate from the $27 the customers paid: false
$27 (paid by the customers) - $2 (kept by the waiter) = $25 (the bill)
22 May 12
Originally posted by forkedknightBut what happened to the $30 they paid?
Surprisingly hard to see how people think about this the wrong way.
The customers each paid $9 x 3 = $27: true
The waiter has $2: true
The waiter's $2 is separate from the $27 the customers paid: false
$27 (paid by the customers) - $2 (kept by the waiter) = $25 (the bill)
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26 May 12
Originally posted by Pianoman1The last bit:
This is similar to the restaurant conundrum:
Three customers go to a restaurant and have a meal. The bill comes to £25. They each a give a £10 note to the waiter. He can't work out how much change to give back to each customer, so he keeps £2 tip and gives £1 back to each customer.
So the customers have paid £9 each, (£27), the waiter has £2. Where is the missing £1?
So the customers have paid £9 each, (£27), the waiter has £2. Where is the missing £1?
9*3 + 2 =....
i.e. it is wrongly adding what the customers have paid in total to what they paid the waiter
Should read:
So the customers have paid £9 each, (£27), the waiter has £2 and the restaurant has its £25
9*3 - 2 = 25
or
So the customers paid £10 each, (£30), the waiter has £2, the customers got back £3 and the restaurant has its £25
10 - 2 - 3 = 25