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**hunkydory19** You have intercepted a long sequence of numbers and noticed that the

most frequently occurring numbers were 13 and 7, in this order. You

know that the ciphertext was obtained with an affine enciphering

transformation with modulus 35, on single letter message blocks of

the ordinary English alphabet A - Z and the letter b for “space”. Find

the deciphering transformation.

I have done so far:

Deciphering transformation of the form: g(y) = cx + d mod 35

Space will be the most frequently occuring, with e the second most frequently occuring.

So b or 26 ---> 13

e or 4 ----> 7

26 = g(13) = 13c + d

4 = g(7) = 7c + d

So 6c = 22 mod 35

But I have no idea where to go from here?!

Could anyone please explain?

Thanks in advance!