two drivers began their journey with the same amount of petrol in their cars at the same time . the only difference is that the first driver � s car could drive 4 hours in that amount of petrol and the second one could drive 5 hours . however , they only drove for some time and found that the amount of petrol that was left in one of the cars was 4 times the petrol left in the other one . for how long had they driven at this point of time ?  Choose the correct choice:	A) 3.75 hours	B) 5.45 hours	C) 7.10 hours	D) 4.75 hours	E) 3.33 hours

Rationale: a 3.75 hours while you can solve it as you like , a simple mathematical equation can be used to find out . let m be the amount of petrol initially . let n be the time for which they drove . according to the question , the amount of petrol used by first car in n hours = mn / 4 the amount of petrol used by second car in n hours = mn / 5 hence , the amount of petrol left in the first car = ( m - mn / 4 ) the amount of petrol left in the second car = ( m - mn / 5 ) as per the details given in the question , we can form the below equation : m - mn / 5 = 4 ( m - mn / 4 ) n = 15 / 4 or 3.75 hours . hence , both the drivers have driven the car for 3.75 hours at that particular time .
Answer: A