A carton contains 20 shirts, of which q are made of pure cotton. After 4 more pure cotton shirts are added to the carton, the probability of drawing a pure cotton shirt becomes 3/4, find the value of q.

14

Step-by-step explanation:

Mathematically, the probability of drawing a pure cotton shirt = number of cotton shirts/Total number of shirts

Firstly, we are to calculate the number of cotton shirts after the addition of the new four

Thus;

Total number of shirts is now = 20+4 = 24

Let the number of cotton shirts be x after the addition

3/4 = x/24

24 * 3 = 4x

x = 72/4

x = 18

Now kindly recall that q became x only because we added 4 new extra cotton shirts

So the number of cotton shirts before the addition = 18-4 = 14