If 'a', 'b' are the 2 positive divisors of N & if (N - a) = 270 & (N - b) = 280, then a > b or in other words a = b + 10
a = N - 270 & b = N - 280, which means N has to start from 280 for 'a' & 'b' to be positive.
285(N) is divisible by 15(a) & 5(b) ====> 15*19 & 5*57 ====> LCM = 15 < 285
288(N) is divisible by 18(a) & 8(b) ====> 18*16 & 8*36 ====> LCM = 72 < 288
300(N) is divisible by 30(a) & 20(b) ====> 30*10 & 20*30 ====> LCM = 60 < 300
315(N) is divisible by 45(a) & 35(b) ====> 45*7 & 35*9 ====> LCM = 315 = 315
are 4 instances for which the above conditions held true. This is partly because as 'a' and 'b' becomes bigger compared to 'N', 'a' and 'b' stop having an LCM lesser than N. In other words 'a' & 'b' will not divide 'N' simultaneously.
