With a boys to girls ratio of 8:7, this means 8/15 of the campers are boys and 7/15 of the campers are girls.
We are told that there are 195 total campers.
To find # of boys: 195 (the total # of campers) x 8/15 (fraction of the campers that are boys) = 104 boys
To find # of girls: 195 (total # of campers) x 7/15 (fraction of the campers that are girls) = 91 girls
Note: If you do not know how to multiply by fractions, let me know, I have another trick that takes more time but doesn't require the use of fractions.