Answer :
Answer:
[tex]\frac{20}{R}[/tex]-[tex]\frac{20}{S}[/tex]
Step-by-step explanation:
Ok, let's pretend that R is 5 and S is 10
That means that Sophie spent 2 hours while Rana spent 4 which means to find the difference you have to subtract. Back to the real problem, we see that we are given R and S not numbers, but variables; as a result, we show the operation then subtract.
Hope this helped my dude.