3: We have a ratio of 3:2 and then 60:x because we multiplied the first ratio by 20 to get the 60 in the second we multiply the 2 by 20 as well and get x=40
4: This one is kind of tricky. we know that there are 4 dogs for every 3 cats. We also know that there are 210 animals. This means that 4x+3x=210 solve this and get x=30 you then multiply the ratio 4:3 by 30 and get 120:90