5^20+5^7/7=? Reminder is…………	Choices:
A) 1  B) 2  C) 3  D) 4  E) 5
5^20 mod 7 + 5^7 mod 7   Since 5 nd 7 are co-primes, we can use Euler's theorem   E(7) = 6   So 5^E(7) = 1   5^20 mod 7 =&gt; (5^6)^3 * 5^2 mod 7   1 * 25 mod 7 = 4   Similarly 5^7 mod 7 =&gt; 5^6 * 5 mod 7   1 * 5 mod 7 = 5   Now 4 + 5 mod 7   9 mod 7 = 2   ANSWER:2
<result>B</result>
5^20+5^7/7=? Reminder is…………