You are given a math word problem and you are supposed to make use of mathematical concepts like probability, combinatorics, linear equations, sequences/series, or simple operators like addition, subtraction, division, or multiplication to answer the given question. Choose the best option from the 5 given options and report that option.

Question: A broker invested her own money in the stock market. During the first year, she increased her stock market wealth by 40 percent. In the second year, largely as a result of a slump in the stock market, she suffered a 30 percent decrease in the value of her stock investments. What was the net increase or decrease on her overall stock investment wealth by the end of the second year?

 Option A: −5%

 Option B: −2%

 Option C: 15%

 Option D: 20%

 Option E: 80%
Option B

Question: A certain sum earns simple interest of Rs. 800 in 2 years at a certain rate of interest. If the same sum earns compound interest of Rs.900in the same period of 2 years, What must be the rate of interest?

 Option A: 25%

 Option B: 10%

 Option C: 15%

 Option D: 20%

 Option E: 30%
Option A

Question: A school has received 60% of the amount it needs for a new building by receiving a donation of $300 each from people already solicited. People already solicited represent 40% of the people from whom the school will solicit donations. How much average contribution is requited from the remaining targeted people to complete the fund raising exercise?

 Option A: $200

 Option B: $177.78

 Option C: $100

 Option D: $277.78

 Option E: $377.78

Option B