The sum of the digits of [(10^x)^y]-64=279. What is the value of xy ?  Choose the correct option:  A) 28  B) 29  C) 30  D) 31  E) 32

Rationale: 1000 − 64 = 936 . whatever xy is you finish with 36 = = > 3 + 6 = 9 therefore , 279 − 9 = 270 and 270 / 9 = 30 now you add the last two digits ( 3 and 6 ) answer is 30 + 2 = 32 answer : e
Answer: E