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pbanavara wrote:This is from the website that Brent had mentioned.

If 6 workers can build 4 cars in 2 days, then how many days would it take 8 workers to build 6 cars?

A. 5/3
B. 9/4
C. 8/3
D. 11/4
E. 10/3

4 cars in 2 days
means 2 cars in 1 day.
Suppose 1 car req 3 unit of work and that means 6 unit of work is produced by 6 workers in 1 day

So, 8 workers will produce 8 Units of work in 1 day
total work - 6cars*(3unit/car,as assumed) = 18 unit

8 units in 1 day
1 unit in 1/8 day
18 unit in 18/8 days
= 9/4 days
Hence B

6 workers, if they build 4 cars in 2 days, they can build 6 cars in 3 days.

if 6 workers 3 days, how about 8 workers same number of cars ?

3x6/8 = 9/4

We all cant be Logitech and do it one line(Wow) so for the less gifted like me here's a solution/explanation

Calculate the rate for 1 worker from 6 workers can build 4 cars in 2 days

6 workers 2 cars 1 day

1 worker rate 1/3 CAR 1 DAY

8 workers rate 8/3

8/3 cars 1day
6cars ?

1/8/3*6 = 3/8*6 = 9/4


Regards,
CR

Thanks guys. Every solution posted is very helpful.

- pradeep

No probs Pradeep! We r all here to learn and help..

Good luck on your GMAT journey!!

let R be the rate of work

so

6* r* 2 = 4

let x days it takes

8* r* x = 6

solve 1 and 2 to get x