UPSC CDS 1 2021 Math Paper

we know that the rule of divisibility by 13 is “if n1n2...... is a number N, then if the number formed by the alternative sum and difference of blocks of 3-3digits from right to left is divisible by 13 then N is divisible by 13”.
So, for 413283P759387 is divisible by 13
387−759+83P−132+4 =83P−500=330+P must be divisible by 13 .
330+P=13(26)−8+P must be divisible by 13. So, P must be 8.