When did he make his mistake and what are the correct solutions?

You receive 15% of the profit from a car wash how much money do you receive from a profit of 300

One number is 4 less than 3 times a second number. if 3 more than two times the first number is decreased by 2 times the second number, the result is 11. use the substitution method. what is the first number?

Ron has 8 caps and 4 of his caps are blue. thes rest of his cap are red. how many of ron's caps are red