How do I know that according to the probability the total is wrong?

Question

There are 4 different coloured counters, red, blue , yellow or green.

The probability for red= 0.10

Blue=0.25

Yellow=0.35

Green=0.3

they all add up to 1

jamie says that there are 70 counters in total... how do i know that he is wrong?

Answer 1

Knowing the total number of counters and the proportion for each color, then you can identify the number of each color. If you try to do this, you should see that 0.25 of 70 is 17.5, indicating there are 17.5 blue counters which would be impossible if we assume counters need to be whole.