Marion’s bike cost $356. Stephanie’s bike is worth twice as much. What is the total price of their bikes? Give the rationale and then the answer.
Let's think step by step. Stephanie's bike costs $356 * 2 = $712. So, their bikes cost $356 + $712 = $1068 in total.. The answer is: 1068.

In 2 years, Maxwell will be twice his sister's age. If his sister is now 2, how old is Maxwell now? Give the rationale and then the answer.
Let's think step by step. In two years, Maxwell's sister will be 2 years + 2 years = 4 years old. Therefore, Maxwell will be 4 years x 2 = 8 years old in two years. Maxwell is now 8 years - 2 years = 6 years old.. The answer is: 6.

Marcus is having a water balloon party. He has 100 balloons. Each balloon holds 3 ounces of water. He can buy 50 ounces of water for $2.5 a bottle. If he walks into the store with 2 $10 bills, how much change will he have after he buys all the water he needs? Give the rationale and then the answer.
Let's think step by step. He will need 300 ounces of water because 100 x 3 = 300. He will need 6 bottles because 300 / 50 = 6. This will cost $15 because 6 x 2.5 = 15. He has $20 because 2 x 10 = 20. He will get $5 in change because 20 - 15 = 5.. The answer is: 5.