Someone help me please

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.)

Identify the initial amount a and the growth factor b in the exponential function. a(x)=680*4.3^x

Reinel saves 30% of every pay check. his paycheck last week was 560$. how much did reniel save last week?