If a varies directly as b and a=4, when b = 2/5, find the equation that relates a and b

Valentino starts with a population of 1,500 amoebas that increases 35% in size every hour for a number of hours, h. the expression 1,500(1+0.35)h finds the number of amoebas after h hours. which statement about this expression is true? a. it is the initial population raised to the growth factor after h hours. b. it is the sum of the initial population and the percent increase. c. it is the sum of the initial population and the growth factor after h hours. d. it is the product of the initial population and the growth factor after h hours.

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.)

Anumber cube is rolled two times in a row. find the probability it will land on 2 on the first roll and a number greater then 4 on the second roll