35-pound mixture of metal includes 20 pounds of aluminum, 10 pounds of nickel and 5 pounds of copper. What is the ratio of mixture to copper?

News cameras take an overhead picture of a crowd at an outdoor event journalist then count the total number of people in the picture and use the sample of estimate the total number of people in the crowd this process is an example of

What value of x is in the solution set of 4x - 12 s 16 + 8x? -10 -9 -8 -7

Having a hard time understanding this question (see attachment).