x:6=2/5
x=6×2/5
x=0.24
3.6x=1.8x3
x=1.8×3÷3.6
x=1.5
276x4=368x
x=276×4÷368
x=3
25x(20-x)=30x15
20-x=30×15÷25
20-x=18
x=20-18
x=2
x:6=2/5
x=6×2/5
x=0.24
3.6x=1.8x3
x=1.8×3÷3.6
x=1.5
276x4=368x
x=276×4÷368
x=3
25x(20-x)=30x15
20-x=30×15÷25
20-x=18
x=20-18
x=2