Set up multiplication/division of ratios to cancel out units you don't need for the final answer and introduce those that you do.
We have m/s and we want m/min so
(100m/s)(60s/min)=6000m/min
So you swap sides and you have 3x=93 and then you divide 3 by 93 and you get x=31
She would make about 17.35 because $850 divided by 49 is 17.3469388 rounded is 17.35
Sophia is more correct in her solution.
