Ineed with this problem so i got 12 but the correct answer is 18. what is the value of |x|+y when x is -3 and y is 15. show how you got 18

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

Need on this geometry question. explain how you did it.

Answer asap ill give ! ’ a sample of radioactive material decays over time. the number of grams, y , of the material remaining x days after the sample is discovered is given by the equation y = 10(0.5)^x. what does the number 10 represents in the equation? a. the half-life of the radioactive material, in days b. the amount of the sample, in grams, that decays each day c. the time, in days, it will take for the samples to decay completely d. the size of the sample, in grams, at the time the material was discovered