Question

There are 3 white marbles, 8 red marbles, 3 blue marbles anf 1 black marbles. predict the number of times out of 300 you will pick a red marble.

Answer 1

prob of picking a red marble
= 8/15

so in 300 picks you would expect
(8/15)(300) or 160 reds

Answer 2

thank you

Is this correct?
8/15 = 0.53

I divided 8 by 15

0.53 * 300 = 159.9

Answer 3

notice you lost a bit of accuracy by rounding off your answer.
8 does not divide by 15 exactly, but 15 divides exactly into 300

If you did this on your calculator, then it should still come out exact, just "chain" your calculations together like this

8x300÷15 or
300÷15x8 or
300x8÷15

all should give you 160