So, we know that 40 hours is $390 and 4 * 10 = 40, therefore, we just have to divide $390 by 4 to get $97.5, meaning that Zoe made $97.5 in 10 hours of work.
84/100 converted to percent is 84%.
Third option is the right answer:
−2x + 4y ≥ 0
The ratio is 91/120 because 91 is only divisible by 1, 7, 13, 91 and 120 is not divisible by 7, 13, or 91 so you cannot reduce this ratio