Question: Karina was born in 1970 and she is currently twice as old as her brother. If her current age is 40, in what year was her brother born?
Answer with step-by-step thinking: If Karina is currently 40, and she is twice as old as her brother, then her brother is currently 40 / 2 = 20 years old. If Karina was born in 1970, then her brother was born in 1970 + 20 = 1990.
So the answer is 1990.


Question: Magdalena has an apple tree on their farm, producing very few apples each year for a while now. However, this year, the apple tree yield was excellent, and it grew 200 apples. Magdalena picked 1/5 of the fruits on the first day, twice that number on the second day, and 20 more apples than he picked on the first day on the third day. Calculate the total number of apples remaining in the tree.
Answer with step-by-step thinking: Magdalena picked 1 / 5 * 200 apples = 40 apples on the first day. On the second day, she picked 2 * 40 apples = 80 apples from the tree. The total number of apples that he picked on the third day is 40 apples + 20 apples = 60 apples. In total, she picked 40 apples + 80 apples + 60 apples = 180 apples in the three days. The total number of apples remaining in the tree is 200 apples - 180 apples = 20 apples.
So the answer is 20.


Question: Ben starts each day with $50, spends $15 every day and saves the rest. After a few days, his mom doubled his total savings and his dad gave him an additional $10. If he now has $500, How many days have elapsed?
Answer with step-by-step thinking:
Let the number of days be x. He saves $50 - $15 = $35 each day. After x days he had saved $35 * x = $35x. His mom doubled his savings to give $35x * 2 = $70x. His dad added $10 to give $70x + $10 = $500. Subtracting 10 from both sides of the equation formed gives $70x = 490. Dividing both sides by $70 give x = 7 days.
So the answer is 7.