[Question]At a certain school, 2/3 of the population are females. One-tenth of the males are foreign students. If the school has 300 students, how many students are non-foreign male students?
[Answer]There are 300 x 2 / 3 = 200 females in the school. So, 300 - 200 = 100 are males. Out of the 100 males, 100 x 1 / 10 = 10 are male foreign students. Thus, there are 100 - 10 = 90 non - foreign male students. The answer is 90.

[Question]In a survey about the student's favorite sports, 40% said they like basketball, 10% like chess, 28% like soccer, and the rest said they like badminton. If 250 students were interviewed, how many students identified chess or basketball as their favorite sport?
[Answer]The total percentage of students who said they like chess or basketball is 10% + 40% = 50%. So, 250 x 50 / 100 = 125 students like chess or basketball. The answer is 125.

[Question]Isabel has some money in her piggy bank. She spent half the amount and bought a toy. She then spent half of the remaining money and bought her brother a book. If she has $51 left, how much money, in dollars, did she have at first?
[Answer]After buying the toy, Isabel has 51 * 2 = 102 dollars left. Isabel had 102 * 2 = 204 dollars at first. The answer is 204.

[Question]Jenny's property tax rate is 2%. Her house is currently worth $400,000. The city is about to build a new high-speed rail project nearby, which will increase her house's value by 25%. Jenny can only afford to spend $15,000/year on property tax. How many dollars worth of improvements can she make to her house before her property tax bill gets too high?
[Answer]
First find how much the rail project will increase the house value by multiplying the initial value by 25%: $400,000 * .25 = $100,000. Then add that amount to the initial value to find the new value: $100,000 + $400,000 = $500,000. Then divide the maximum amount of property tax Jenny can afford to pay by the property tax rate to find the maximum value her house can have: $15,000 / .02 = $750,000. Now subtract the house's value after the rail project from the maximum value to find how much value the improvements can have: $750,000 - $500,000 = $250,000. The answer is 250000.