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.

[Q]: Question: A tank holds x gallons of a saltwater solution that is 20% salt by volume. One Fourth of the water is evaporated, leaving all of the salt. When 5 Gallons of water and 10 gallons of salt are added, the resulting mixture is 33 1/3 % salt by volume. What is the value of x?

 Option A: 37.5

 Option B: 75

 Option C: 100

 Option D: 150

 Option E: 175
[A]: Option B


[Q]: Question: A boat can travel with a speed of 25km/hr in still water. If the speed of the stream is 5km/hr, find the time taken by the boat to go 120km downstream.

 Option A: 1 hr

 Option B: 2 hrs

 Option C: 3 hrs

 Option D: 4 hrs

 Option E: 5 hrs
[A]: Option D


[Q]: Question: A student scored an average of 60 marks in 3 subjects: Physics, Chemistry and Mathematics. If the average marks in Physics and Mathematics is 90 and that in Physics and Chemistry is 70, what are the marks in Physics?

 Option A: 86

 Option B: 160

 Option C: 76

 Option D: 140

 Option E: 26
[A]:
Option D