Three siblings are born 5 years apart, each. If the eldest child is 20 years old now, what's the total of the ages of the three siblings 10 years from now? Give the rationale and then the answer.
Let's think step by step. Ten years from now, the elder child will be 20 + 10 = 30 years old. If the elder child is 20 years old now, the second born is 20 - 5 = 15 years old, 5 years younger than the firstborn. The second - born will be 15 + 10 = 25 years old ten years from now. The total age of the first and second - born 10 years from now will be 25 + 30 = 55. The third - born who is five years younger than the second born is 15 - 5 = 10 years old. The third sibling's age ten years from now will be 10 + 10 = 20 years old. The total age of the three siblings ten years from now will be 55 + 20 = 75 years.. The answer is: 75.

Jane bought 2 skirts for $13 each. She also bought 3 blouses for $6 each. She paid the cashier $100. How much change did she receive? Give the rationale and then the answer.
Let's think step by step. The 2 skirts cost $13 x 2 = $26. The 3 blouses cost $6 x 3 = $18. The total cost for 2 skirts and 3 blouses is $26 + $18 = $44. Jane received $100 - $44 = $56 change.. The answer is: 56.

There are 400 students. 120 students take dance as their elective. 200 students take art as their elective. The rest take music. What percentage of students take music? Give the rationale and then the answer.
Let's think step by step. There are 400 - 120 - 200 = 80 students in music. Thus, students in music make up (80 / 400) * 100 = 20% of the students.. The answer is: 20.