52+53+54+...+5247 = (52+53+54+55)+54(52+53+54+55)+58(52+53+54+55)+512(52+53+54+55)+ ... +5240(52+53+54+55)+5244(52+53) = (3900)+54(3900)+58(3900)+512(3900)+ ... +5240(3900)+5244(150) Since 3900 is divisible by 52 we only need to look at the remainder when 5244(150) is divided by 52 5244(150) = (5244-1+1)(150) = (5244)(150)-1(150)+1(150) = 150[(5244)-1]+150=150[(54)61-1] + 150 Since xk-1 is divisible by x-1, (54)61-1 is divisible by 54-1 or 624 which is divisible by 52, so we only need to find the remainder when 150 is divided by 52 2 52)150 104 46 Answer: 46 Edwin