If P is a multiple of 140, and Q is 7^x, we need to see what values are available for R/S.Factors of 140 will help us determine if (when reduced) the value will be divisible by 5.1-2-4-5-10-14-28-35-70-140.Some available numbers for Q:7-49-343-2401...(I stopped doing the math, because there is a useful principle here).The only factors of (7^x) will be the number itself and the numbers ahead of it