X
It is now four years since I first asked for support, and I would like to sincerely thank everyone who has helped me. BrainBashers doesn't show adverts, and I continue to depend on the ongoing support from everyone who enjoys the site.
support BrainBashers
???
Puzzle 21
Tuif cumzye if n fizpye trsg go sre hbw ensl n EOG13 caet eaceyctrd phzmlr paa oe. Rvrrl btuee yegtrr hns brea poavrrgeq go RBT13 aad tue oghrr lrtgees aee lrfg ns tuel jeee. Oug, ybu mny afk, jhnt if ghr cumzye? Wrly, hbw mnnl joedf nrr vn tuif cumzye!
This puzzle is a simple test to see how easy a ROT13 part encrypted puzzle can be. Every other letter has been converted to ROT13 and the other letters are left as they were. But, you may ask, what is the puzzle? Well, how many words are in this puzzle!
ROT13 replaces each character with the one 13 places away.
A = N, B = O, C = P, D = Q, E = R, F = S, G = T, H = U, I = V, J = W, K = X, L = Y, M = Z, N = A, O = B, P = C, Q = D, R = E, S = F, T = G, U = H, V = I, W = J, X = K, Y = L, Z = M.
The length of each word is the same length as the numbers one, two, three, four, five, six, etc.
The next number is SEVEN, which has 5 letters, and llama is the only word with 5 letters.
???
Puzzle 23
The local CD shop operates an unusual discount policy. The discount on the next purchase is worked out on the current purchase in the following way: for every whole pound spent you get 0.5% discount on the next purchase. For example, if you purchased £8.99 on the first purchase, you would then get a 4% discount on the next purchase and so on. You can make as many purchases as necessary.
You need to buy 7 CDs, costing, £11.50, £12.00, £12.00, £12.50, £13.00, £13.00 and £14.50. What is the cheapest method of buying them?
Answer
Purchase 1: £11.50, £12.00, £12.00, £12.50 = £48.00 (which gives a 24% discount on the next purchase). Purchase 2: £13.00, £13.00, £14.50 = £40.50 minus 24% discount = £30.78. For a total cost of £78.78.
Reasoning
Since no digit is duplicated, neither number can end in 1, otherwise, the last digit of the answer would already have been used.
Neither number can end in 5 because the answer would then end in 5 or 0.
So the first number can only be 62, 63, 64, 67, or 68.
We can now look at what the second number can end with, and we find that …
if the first number was 62, the second number can only end in 4 or 7.
Why …
not 1 as previously explained
not 2 because we've already used that in the 62
not 3 because 62 x *3 would end in 6, which is already in the 62
not 5 as previously explained
not 6 because we've already used that in the 62
not 8 because 62 x *8 would end in 6, which is already in the 62
We can repeat this for the other possible first numbers and find that …
if the first number was 62, the second number can only end in 4 or 7.
if the first number was 63, the second number can only end in 4, 7, or 8.
if the first number was 64, the second number can only end in 2, 3, 7, or 8.
if the first number was 67, the second number can only end in 2, 3, or 4.
if the first number was 68, the second number can only end in 3 or 4.
Let's check these in turn …
If the first number was 62, the only possible values are:
62 x 14 = 868
62 x 34 = 2108
62 x 54 = 3348
62 x 74 = 4588
or
62 x 17 = 1054
62 x 37 = 2294
62 x 57 = 3534
62 x 87 = 5394
Only 4 calculations are required for each option, as we didn't need to check 62 x 84 as we already know that the answer would end in 8, or 62 x 47 as we already know that the answer would end in 4.
All of these answers fail as they don't contain all of the digits.
Similarly, we can look at 63, then 64, etc. For each of the numbers, we have to check the possible endings, but in each case, only 4 calculations are required (as seen in the examples above).
It is now four years since I first asked for support, and I would like to sincerely thank everyone who has helped me. BrainBashers doesn't show adverts, and I continue to depend on the ongoing support from everyone who enjoys the site.
