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 cistern can be filled by a tap in 3 hours while it can be emptied by another tap in 9 hours. If both the taps are opened simultaneously, then after how much time will the cistern get filled?

 Option A: 2.9 hrs

 Option B: 4.5 hrs

 Option C: 2.9 hrs

 Option D: 7.2 hrs

 Option E: 8.6 hrs
Option B

Question: A car dealership has 40 cars on the lot, 30% of which are silver. If the dealership receives a new shipment of 80 cars, 40% of which are not silver, what percentage of total number of cars are silver?

 Option A: 35%

 Option B: 37.5%

 Option C: 45%

 Option D: 47.5%

 Option E: 50%
Option E

Question: The proportion of the ages of Pooja and Charlie is 2 : 5, After 8 years, their ages will be in the proportion of 1 : 2. Then what is the variance in their current ages?

 Option A: 36 years

 Option B: 28 years

 Option C: 24 years

 Option D: 19 years

 Option E: 30 years

Option C