Person A can finish a job in m days, and person B can finish it in n days. What's the fraction they finish if they work together for one day

300b(x) is graphed by the functio

1. 0.3 •4 is the same as 4 groups of 0.32. 7•0.8 is the same as 7 groups of 0.83. it increases by 0.5 every time, so 0.5x4 it increases by 0.9 every time, so 0.9x5. 0.9•12=10.86. 0.47•5=2.35i can finish the next ones in a separate post

What mathematical statement is missing ? ? the answer is b