So Tina has been dieting for 13 weeks
On week 1: She lost 3 pounds, so +3 pounds
On week 2: She gained a pound, so - 1 pound
On each remaining week, she lost 2 pounds, so,
On week 3: She lost 2 pounds, so +2 pounds
On week 4: She lost 2 pounds, so +2 pounds
On week 5: She lost 2 pounds, so +2 pounds
On week 6: She lost 2 pounds, so +2 pounds
And so on,,,
So losing 2 pounds each week for 11 weeks would equal, 2 pounds x 11 weeks = 22 pounds
So, add that all up: 3 pounds - 1 pound + (2 x 11 weeks) = 24 pounds total
