Solve the congruence 2n≡15(mod47), as a residue modulo 47. (Give an answer between 0 and 46.)
The inverse of 2 modulo 4 is 17, so n = 15*17 = 255 = 20 (mod 47).
2n mod 47 ==15, solve for n
n ==31
2*31==62
62 mod 47 ==15
+6 
