Respuesta :
6/15 simplified is 3/5 so the ratio can be written as:
3 to 5
3:5
3/5
3 to 5
3:5
3/5
It's 6:15 because order is important and you see you have 6 boy and 15 girls well then boy will be first then girls but you got to simplify so it will be 3/5 or 3:5 or 3 to5