Alice has 20 quarters. She wants to exchange them for nickels and so she goes to the bank. After getting back from the bank, she discovers that 20% of the nickels are iron nickels worth $3 each. What is the total value of her money now? Give the rationale and then the answer.
Let's think step by step. A quarter is worth five nickels because .25 / .05 = 5. She gets 100 nickels from the bank because 20 x 5 = 100. 20 of the nickels are iron nickels because 100 x .20 = 20. 80 of the nickels are regular because 100 - 20 = 80. The iron nickels are worth $60 because 20 x 3 = 60. The regular nickels are worth $4 because 80 x .05 = 4. Her money is now worth $64 because 60 + 4 = 64.. The answer is: 64.

Ann is cutting fabric to make curtains. She cuts a 4 foot by 6 foot rectangle for the living room, and a 2 foot by 4 foot rectangle for the bedroom. If the bolt of fabric is 16 feet by 12 feet, how much fabric is left in square feet? Give the rationale and then the answer.
Let's think step by step. First figure out how many square feet the original bolt of fabric was: 16 feet * 12 feet = 192 square feet. Then figure out how much fabric Ann took for the living room curtains: 4 feet * 6 feet = 24 square feet. Then figure out how much fabric Ann took for the bathroom curtains: 2 feet * 4 feet = 8 square feet. Finally, subtract the square footage of both sets of curtains from the total square footage: 192 - 24 - 8 = 160 square feet.. The answer is: 160.

John climbs 3 staircases. The first staircase has 20 steps. The next has twice as many steps as the first. The final staircase has 10 fewer steps than the second one. Each step is 0.5 feet. How many feet did he climb? Give the rationale and then the answer.
Let's think step by step. The second flight had 20 * 2 = 40 steps. The third had 40 - 10 = 30 steps. So in total, he climbed 20 + 40 + 30 = 90 steps. So he climbed 90 * .5 = 45 feet.. The answer is: 45.