Forget this question. It is badly formulated.

First of all the OA is not 14 but 13/15. it is impossible to get a whole number from the statement above.

1/5 of the entire lot is red so 20 cars. Of this 2/3 ar convertible, which means that 13.3 cars are of this type. Which is impossible: you must have a whole number of cars.

Anyway, if we wanna solve we do have 13 cars not covertible over 15. The answer is 13/15.

Hope this helps.

PS: this is an easy question NOT hard.

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