Parker went to the gym and found 4 twenty pounds dumbbells set up for weightlifting. He added two more dumbbells to the setup and started his exercises. How many pounds of dumbbells is Parker using for his exercises? Give the rationale and then the answer.
Let's think step by step. 4 twenty - pound dumbbells weigh 4 * 20 = 80 pounds. When Parker added two more dumbbells to the setup, he increased the weight by 2 * 20 = 40 pounds. The dumbbells that Parker used to do his exercise weigh a total of 40 + 80 = 120 pounds.. The answer is: 120.

After Betty gave Stuart 40% of her marble collection, the number of marbles in Stuart's collection increased to 80. If Betty had 60 marbles, how many marbles did Stuart have initially? Give the rationale and then the answer.
Let's think step by step. If Betty had 60 marbles, she gave Stuart 40 / 100 * 60 = 24 marbles. Since the number of marbles in Stuart's collection increased to 80 after Betty gave him 24 marbles, the number of marbles he initially had is 80 - 24 = 56.. The answer is: 56.

Savannah is wrapping presents for her friends and family for Christmas. She has bought 3 rolls of wrapping paper to wrap 12 gifts. If it takes 1 roll to wrap 3 gifts and 1 roll to wrap 5 other gifts, if there is no wrapping paper leftover after Savannah wraps the rest of the gifts, how many gifts did she wrap with the third roll of paper? Give the rationale and then the answer.
Let's think step by step. Savannah has 12 gifts to give her friends and family and has already wrapped 3 gifts + 5 gifts = 8 gifts already wrapped with the first two rolls of paper. She started off with 12 gifts to wrap and has already wrapped 8, 12 - 8 = 4 gifts she wraps with the third roll of paper.. The answer is: 4.