20 points!!! (PLEASE ANSWER ALL, AND ALL CORRECTLY!!) this test is already late!
At the zoo, the ratio of mammals to reptiles is 4:3. There are 20 mammals in the zoo.

(a) How many reptiles are in the zoo?


(b) If the zoo adds 12 more mammals to its collection, how many more reptiles will they have to add to keep the ratio the same?


(c) A zoo in a different city has a ratio of mammals to reptiles of 6:5. Which zoo has the larger ratio of mammals to reptiles?
 
Thank you!