Final answer:
The revenue earned from digital sales in each of the three categories is $11.6 million for pop/rock music, $3.6 million for tropical music, and $6.4 million for urban Latin music.
Step-by-step explanation:
To find the revenue earned from digital sales in each category, let's set up equations using the given information:
Let's say the revenue from pop/rock music is x million dollars.
According to the given information, pop/rock music brought in twice as much as the other two categories combined. Therefore, the revenue from tropical and urban Latin music combined is x/2 million dollars.
It is also mentioned that the revenue from pop/rock music is $8 million more than tropical music. So, the revenue from tropical music is x - 8 million dollars.
Adding up the revenues from the three categories, we have the equation:
x + (x/2) + (x - 8) = 21
Simplifying this equation, we get:
2x + x + 2x - 16 = 42
Combining like terms:
5x - 16 = 42
Adding 16 to both sides:
5x = 58
Dividing both sides by 5:
x = 11.6
Therefore, the revenue earned from digital sales in each of the three categories is:
pop/rock music $11.6 million
tropical music $3.6 million
urban Latin music $6.4 million