Bunuel wrote:

Bunuel wrote:

A company’s four cars running 10 hrs a day consume 1200 lts of fuel in 10 days. In the next 6 days, the company will need to run 9 cars for 12 hrs each so it rents 5 more cars which consume 20% less fuel than the company’s four cars. How many lts of fuel will be consumed in the next 6 days?

(A) 1200 lt

(B) 1555 lt

(C) 1664 lt

(D) 1728 lt

(E) 4800 lt

Kudos for a correct solution.

VERITAS PREP OFFICIAL SOLUTION: First let’s try to figure out what is meant by ‘consume 20% less fuel than the company’s cars’. It means that if company’s each car consumes 1 lt per hour, the hired cars consume only 4/5 lt per hour. So renting 5 more cars is equivalent to renting 4 cars which are same as the company’s cars. Hence, the total number of cars that will be run for the next 6 days is 8 company-equivalent cars.

4 cars running 10 hrs for 10 days consume 1200 lt of fuel

8 cars running 12 hrs for 6 days consume x lt of fuel

\(x = 1200*(\frac{8}{4)}*(\frac{12}{10})*(\frac{6}{10}) = 1728\) lt

We multiply by 8/4 because more cars implies more fuel so we multiply by a number greater than 1.

We multiply by 12/10 because more hours implies more fuel so we multiply by a number greater than 1.

We multiply by 6/10 because fewer days implies less fuel so we multiply by a number smaller than 1.

Answer (D)Why can't we interpret the question as below:

The question says "5 more cars which consume 20% less fuel than the company’s four cars" but it doesn't say "5 more cars

EACH OF WHICH consumes 20% less fuel than

EACH OF the company's four cars".

What I mean to say is it could be interpreted as "all the 5 new cars consume 80% of what all the four cars consume"

If we interpret it that way then it should be "1.8*fuel consumed by 4 cars = 864*1.8 = 1555.2 lt"

Any thoughts?