Answer:
280
Explanation:
For ease of comparison $20/hr < $12/hr+ commission, let's do it by the hour first.
Hourly pay of the food truck is $12, every burger she sells, she gets 10% of the $12 burger, which is $1.2. Therefore all we need to figure out is 1.2x +$12 > $20. Minus both sides by 12, now all we have is down to the bare minimum: 1.2*X = $8
8 divided by 1.2 is 6.66 (infinite), but since she can't sell 0.6 of a burger, we need to round up, which is 7, keep in mind we are still at hourly. Now we know that she has to sell at least 7 burgers every hour she's working for the food truck, it's a 40-hour work week, 7*40 is 280.
Check:
Food truck: $12+ 12*0.1*7 = $20.4/hr $20.4 > $20
Best of luck for your SAT!
