Final answer:
The boosters organization bought 12 basketballs and 16 footballs.
Step-by-step explanation:
Let's assume that the number of basketballs bought is x. Since they bought 4 more footballs than basketballs, the number of footballs bought is x+4. The cost of each basketball is $14.00 and the cost of each football is $21.00. We can set up the following equation to represent the total cost of the balls:
14x + 21(x+4) = 504
Simplifying the equation:
14x + 21x + 84 = 504
Combining like terms:
35x + 84 = 504
Subtracting 84 from both sides:
35x = 420
Dividing both sides by 35:
x = 12
Therefore, they bought 12 basketballs and 16 footballs.