Suppose in one year total revenues from digital sales of pop

Suppose in one year, total revenues from digital sales of pop/rock, tropical (salsa/merengue/cumbia/bachata), and urban (reggaeton) Latin music in a certain country amounted to $27 million. Pop/rock music brought in twice as much as the other two categories combined and $11 million more than tropical music. How much revenue was earned from digital sales in each of the three categories?

Solution

Consider:

Sales from Pop/rock = P; Sales from Tropical = T & Sales from Urban Latin music = U

Hence, as stated in question: P+T+U = $27m - Eq.1

Also, it is stated that, Pop music brought in twice as much as the other two categories combined, hence: P=2(T+U) - Eq.2

Also it is stated that Pop music brought in $11m more than tropical music, hence: P-T=$11m - Eq.3

Solving Eq.1 & Eq.2, we get,

3T+3U=27

=>T+U=9 - Eq.4

Keeping value from Eq.4 in Eq.1; we get P=$18m

Putting value of P in Eq.3, we get T=$7m

and in Eq.4, we get U=$2m

Hence, Pop/rock music sales = $18million

Tropical sales = $7million

and Urban latin music sales = $2million