I tried solving this for 20 minutes straight, please help

Which fraction is not equivalent to 8/12 a. 2/3 b. 24/36 c. 4/10 d. 6/10

Determine the number of girls in a math class with 87 boys if there are 25 girls for every 75 boys

Gabriel determined that his total cost would be represented by 2.5x + 2y – 2. his sister states that the expression should be x + x + 0.5x + y + y – 2. who is correct? explain.