Answer:
16
Step-by-step explanation:
since 4/5 have a pet, you would divide by 5.
30÷5=6
but since only 4 have a pet, you would multiply that by 4 to get 4/5
6×4=24
24 students have pets
now you would divide by 3, as 2/3 have a dog
24÷3=8
but only 2/3 have dog, so you would multiply by 2
8×2=16
I'm sure there is a simpler way but this is how I would do it.