Hurry me how did they get the answer for part c? ?

Players on the school soccer team are selling candles to raise money for an upcoming trip. each player has 24 candles to sell. if a player sells 4 candles a profit of$30 is made. if he sells 12 candles a profit of $70 is made

What is the best way to answer questions with a x expression in the question. for example 3x + 10x=?

Measure of angles 31 (x+4) (3x+9) me