A problem by Arpit Sah
Let there be 'n' positive integers between 100 and 1000, which are divisible by 7. If 'n' can be represented as + +1, then find a+b.
The answer is 13.
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1 solution
No of positive integers divisible by 7 between 100 and 1000 is 128 So, 128 = a 2 + b 3 + 1 127 = a 2 + b 3 We check for b = 5 , 4 , 3 ( Since the value of a square is always positive ) For b = 3 , we get a = 10 So, a + b = 1 3