25 : 15 Divide both by 5, since they are divisible by 5 [tex] \frac{25}{5} : \frac{15}{5}
[/tex] 25 divided by 5 is 5 ; 15 divided by 5 is 3 so 5 : 3 5 : 3 is lowest terms since nothing can be divided again, 5 is in lowest terms, 3 is in lowest terms.