Mark: (Hail the all conquering hero)
ABC+DEF+GHI=JJJ
J=9
Since there are no leading zeros, J must be 7, 8, or 9, since JJJ = ABC + DEF + GHI ≥ 100+240+350 = 690. Now, the remainder left after dividing any number by 9 is the same as the remainder left after dividing the sum of the digits of this number by 9. Next note that 0 + 1 + ... + 9 has a remainder of 0 after dividing by 9, and since JJJ has a remainder of 0, 3, or 6, it follows that J must be 9, since it's the only number from 7, 8 and 9 that leaves a remainder of 0, 3, or 6 if you remove it from the sum 0 + 1 + ... + 9.
BETS
You are Molly
Waldo started with 30 cents
Spike started with 40 cents
Let Waldo start with w, Molly with m, and Spike with s. Following the above account we get the following progression of monies:
W = 2*w, M = m-w
M = 2*(m-w), S = s-(m-w) = s+w-m
S = 2*(s+w-m), W = 2*w-(s+w-m) = w+m-s
And so Waldo finished with w+m-s, Molly with 2*(m-w), and Spike with 2*(s+w-m). Since these must all be equal, we have three equations and three unknowns, so solve; this gives us that 4*m = 5*s and 3*s = 4*w. Now, if s = 1/2 this implies that w = 3/8 = 37.5 cents, an impossible amount of money to start with. If w = 1/2 this implies that s = 2/3, again an impossible amount to start with. Finally, if m = 1/2 this implies that s = 2/5 = 40 cents, w = 3/10 = 30 cents, which works. It follows that I am Molly.
PYRAMID
I think we need to know the area of the base. Or are we to figure out the largest pyramid that can be completed before the work force is exhausted?
Assuming the latter, it will take 53 days to build a pyramid 46 levels (138m) high. If a crew member dies whether or not his crew layed a block, then 1416 survive. Otherwise, since only 15 blocks are layed the last day, 1489 would have survived.
Each block added results in the death of exactly one slave, and when there are less than 17 slaves no more blocks may be added, so the pyramid consists of at most 35000-16 = 34984 blocks. The first level needs 1 block, the next 4, and in general the ith level requires i^2 blocks, and so a pyramid n levels tall requires 1 + 2^2 + 3^2 + ... + n^2 = n(n+1)(2n+1)/6 blocks. This is between n^3/3 and (n+1)^3/3, and solving n^3/3 = 34984 we get that the maximum number of levels is either 46 or 47, with a quick check showing that 46 is correct.
It follows that the pyramid is 46*3 = 138 meters tall, consists of 33511 blocks, and the number of slaves surviving the construction is 35000-33511=1489.
To compute the number of days required for construction, note that if there are m slaves on a given day the number of blocks added is between m/17 and m/17 - 16/17, and given k days it can be easily shown that the number of blocks added is between m/17 + (16/17)m/17 + ... + (16/17)^{k-1} m/17 and m/17 + (16/17)m/17 + ... + (16/17)^{k-1} m/17 - k*16/17; summing the geometric series we get m*(1-(16/17)^k), and so to find the number of days required we solve 35000*(1-(16/17)^k) = 33511 and get that (16/17)^k = .04254 or k=52.08.
Since this came from an upper bound on the number of blocks, it's a lower bound on the number of days; thus, it'll take at least 53 days to build the pyramid. Checking the lower bound, we see that the number of blocks that can be added in 53 days is greater than 33542, and so the pyramid can indeed be built in 53 days.
PHONE NUMBER
There are two solutions without leading zeros in either the dividend or the divisor:
879-9912 and 989-9901
PRODIGITIOUS
I already answered this last December, so I'll leave it for others.
No way will that question ever be answered again. Far too difficult.
Mark proving what a foil I am writes, "20,763mm = 20.763m (better go for another lie-down"
Hey! I'm already horizontal. I am ?'working' under difficult conditions here!
Yitwail, "but when shooting spares, maybe spin is omitted"
OK! OK! You win. When ?'shooting spares' if asked the answer to that riddle it is as you gave. However, at all other times it is as stated. :wink:
Scheesh, the next thing we will be discussing is; what proportion of a ball's travel is ?'slide' before forward revolution takes over?
Whim, good problem. Mark made it look easy, but if you saw all my scribbles it was anything but.
Classic Riddles
1. Think fast: There's an electric train traveling south. The wind is from the north-west. In which direction would the smoke from the train be blowing
2. What is the second most used letter in the English language
Hint: it is also the first letter of the most used word in the English language.
3. In an unabridged dictionary, what 3 letter word has the most definitions
4. How can you avoid hitting your fingers when driving in a nail with a hammer
5. Why did the bubble gum cross the road
6. What walks on 4 legs in the morning, 2 legs in the afternoon, and 3 legs in the evening
7. What 5 letter word can have its last 4 letters removed and still sound the same
8. If you see a bird sitting on a twig, how could you get the twig without disturbing the bird
A prime number is a whole number, greater than 1, that is divisible only by itself and 1. Some examples of prime numbers are 2, 3, 5, 7, 11, and 13. What is the largest prime number, P, such that 9 times P is less than 400
The numbers M and N are different numbers selected from the first twenty-five counting numbers:
1, 2, 3, 4, ... , 24, 25. If M is larger than N, what is the smallest value that the expression at the right can have
M x N
_______
M - N
A printer has to number the pages of a book from I to 150. Suppose the printer uses a separate piece of type for each digit in each number. How many pieces of type will the printer have to use
A jar contains a large number of pennies. The pennies can be divided into equal shares among 3, 4, 5, 6, 7, or 8 children with no pennies left over each time. What is the least number of pennies the jar could contain