So, in this problem you already have the equations set up for how much money each one works. You have Jim, earning a starting amount of $35, plus an additional $3 for every hour he works. You also have John, who gets $8.
The variable in the equations is h, which stands for hours. From there, you can put the three different h values (6, 7, and 8) into the equations to see who gets more money.
For instance, for Day 1, Jim gets 35+3x6 dollars, or 35+18=$53, while John gets 8x6 dollars, or $48. You can substitute in 7 and 8 and do the same process to get the answers for Day 1 and 2.
Hope this helps!