Question

you have 16 checkers the ratio of black to red is 3 to 5,  how many black checkers are there?

Answer 1

The ratio of black to red is 3 to 5, so it's sort of like you have sets of 3+5 = 8 checkers.

If you have 16 checkers then you have 16/8 = 2 sets.

2 sets would have 2*3 = 6 black checkers.

2 sets would have 2*5 = 10 red checkers.

Answer:  6 black checkers.