PLEASE HELP ME FAST IM CONFUSED!

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.)

Twice the sum of a number and 4 is equal to three times the difference of the number and 7. find the number.

The ratio of the measures of the three angles in a triangle is 2: 9: 4. find the measures of the angels