In a box of marbles, the ratio of red
marble to total marble is 2 :5, the
ratio of green marble to the total
marble is 3:10 . If the marbles that are
neither red nor green are blue, how
many marbles are in the box if there
are 40 marbles in the box
A mountain trail is 12.1 mile long. If
a hiker walks along the trail at rate of
1.96 miles per hour approximatly,
how many hours will the hiker walk
the entire trail
A population of 15 items. 4 red, 6 black and 5 green. a sample of 4 items are selected. what is the probability that the sample contains 3 black and 1 green?