Let cats = X
Then doges = 6x ( 6 times as many cats, so multiply 6 by number of cats)
Now you have X + 6X = 35 ( number of cats plus number of doags equal 35)
X +6x = 35
Simplify:
7X = 35
Divide both sides by 7 to solve for x:
X = 35 / 7
X = 5
Cats = X, so there are 5 cats.
Dogs = 6X = 6(5) = 30 total dogs.