Tina has been dieting for a total of 13 weeks. she lost 3 pounds on the first week of her diet, but gained back a pound on the second week. on each remaining week of her diet, she lost 2 pounds. how many pounds has tina lost in all

So let's say tina weighs 110 pounds
She looses 3 on the first week so now she weighs 107
She gains back 1 pound on the 2nd week so now she weighs 108 
there are 11 weeks left and she looses 2 pounds per week so you take 108-22 which will equal 86 pounds
Now you take her starting weight and subtract it by her weight at the end of 13 weeks

110-86= 24

Tina looses 24 pounds.

**I choose a random starting weight, you can choose any starting weight and still have the same answer.