a+b=20(where a is number of clerks and b the number of manager)

Also 11.5a+19b=13*20=260

Solving for both the equations(19a+19b=380,11.5a+19b=260) and substracting, we will get 7.5a=120 or a=16)

Now since 4 new clerks were added and few members were promotes, we have 20-x clerks now and 4+x managers.

Also given that

11.5(20-x) + 19(4+x) = 24*14

230 + 76 + 7.5x = 336

7.5x = 30 or x=4(Option B)

Sent from my LG-H818 using

GMAT Club Forum mobile app
_________________

You've got what it takes, but it will take everything you've got