Isabelle gets a job so she can save enough money to go to a concert with her two brothers. Her ticket costs $20. Her brothers both get the children’s discount, and each of their tickets cost $10. Her brothers have saved $5 between the two of them and Isabelle has saved $5. If her job pays $3 per week, how many weeks must she work to afford the tickets? Give the rationale and then the answer.
Let's think step by step. The tickets for both of her brothers will cost her $10 * 2 = $20. To buy tickets for all of them, it will cost Isabelle $20 + $20 = $40. Between all of them, they have saved a total of $5 + $5 = $10. Since they have already saved $10, she needs to earn an additional $40 - $10 = $30 to afford the tickets. Since she makes $3 per week, it will take her $30 / ($3 / week) = 10 weeks to save enough money for all of the tickets.. The answer is: 10.

Archie needs to lay sod in his backyard that measures 20 yards by 13 yards. He has a shed on it that measures 3 yards by 5 yards. How many square yards of sod will Archie need for his backyard? Give the rationale and then the answer.
Let's think step by step. 20 * 13 = 260 square yards. 3 * 5 = 15 square yards. 260 - 15 = 245 square yards. Archie needs 245 square yards of sod.. The answer is: 245.

Kim's TV uses 125 watts of electricity per hour. She runs it for 4 hours a day. If electricity cost 14 cents per kw/h how many cents does her TV cost to run for a week? Give the rationale and then the answer.
Let's think step by step. She uses 4 hours / day * 125 watts / hour = 500 watt hours / day. That means she uses 500 watt hours / day * 7 days / week = 3500 watt hours / week. This is 3500 watt hours / 1000 watts / kw = 3.5 kw hours. So her TV cost 3.5 kw hours / week * $0.14 / kw hour = $0.49 / week.. The answer is: 49.