15:80=( 15/5):(80/5)=3: 16

0. 125:( 1/8)=0. 125:0. 125= 1: 1

0.4:( 1/8)= 0.4/( 1/8)= 0.4x(8/ 1)= 3.2/ 1 = 32/ 10 = 16/5 = 16:5

0.4:( 1/8)=(2/5):( 1/8)=(2/5)/( 1/8)=(2/5)x8 = 16/5 = 16:5

Second, the ratio:

160:200= 160/200=0.8

3.7: (7.4) = 3.7/(7/4) = 3.7x (4/7) =14.8/7 = (about) 2. 1 1.

(2/3):(8/9)=(2/3)/((8/9)=(2/3)x(9/8)= 18/24 = 3/4 = 0.75

0.3t:200kg = 300kg:200kg = 1.5