You are given a ciphertext that you are told was encrypted with one of the three historical encryption methods: transposition cipher, monoalphabetic cipher, polyalphabetic cipher. You are also told that the plaintext is an English language document. Concisely explain how you can use the single letter frequencies of the ciphertext letters to help you to determine which encryption method may have been used. For each encryption method, explain whether using only single letter and bigram/trigram frequencies are sufficient to cryptanalyse a ciphertext.

To hide gridline when you display or print a worksheet

The “rule of 72” is used to approximate the time required for prices to double due to inflation. if the inflation rate is r%, then the rule of 72 estimates that prices will double in 72/r years. for instance, at an inflation rate of 6%, prices double in about 72/6 or 12 years. write a program to test the accuracy of this rule. for each interest rate from 1% to 20%, the program should display the rounded value of 72/r and the actual number of years required for prices to double at an r% inflation rate. (assume prices increase at the end of each year.)

The fourth generation of computers emerged between 1970s and 1980s. which technological advancement brought about this generation of computers? which computer architecture was used most in this generation?