Not too sure how to do this, anyone understand? ?

Use the frequency distribution, which shows the number of american voters (in millions) according to age, to find the probability that a voter chosen at random is in the 18 to 20 years old age range. ages frequency 18 to 20 5.9 21 to 24 7.7 25 to 34 20.4 35 to 44 25.1 45 to 64 54.4 65 and over 27.7 the probability that a voter chosen at random is in the 18 to 20 years old age range is nothing. (round to three decimal places as needed.)

Find the midpoint m of z1=(8+5i) and z2=(12+3i)

The length of a rectangle plus its width is 25 cm. the area is 156 square cm. what are the length and width of the rectangle? separate the answers with a comma.