Answer:
#18 $8000
#19 $180
Step-by-step explanation:
#18: She bakes 500 muffins on Saturday. If she bakes 3 times as many on Sunday, 500*3=1500. 1500 plus the original 500 muffins is 2000 muffins. 2000*4=$8000 made.
#19: Jack has $80 more than Eric. So if Eric's amount of money is x, then Jack's amount of money is x+$80. When Jack spends $30, then Jack only has x+$50 because 80-30 is 50. If Jacks amount of money is 2 times the amount Eric has, then x+$50 must equal 2x. Subtract x from both sides to get 50=x. So, Eric has 50 dollars. This means that Jack has 130 dollars. 50+130= $180.