There are 10 counters in a box a counter is chosen and replaced 100 times the results are 58 blue and 42 red how many of each colour do you think there are in the box

Because the picking was done 100 times, the number of times a counter appeared is the equivalent of its percentage
So blue was picked 58% of the time, and red picked 42% of the time
Then
58% of 10 is 5.8
42% of 10 is 4.2
Since you can't have portions of a counter, you have to round the two numbers to the nearest integer, so there were 6 blue counters and 5 red counters. The reason they deviate slightly from this value is just because of random outcome