Question

Fir trees :yew trees is 3:4. There are 18 fir trees, how many yew trees

Answer 1

There would be 24 yew trees
3:4 becomes 18:24
You have to multiply 3 by 6 so you multiply the 4 by 6 as well

Answer 2

F/y=3/4
3/4=18/y
times both sides by 4y aka cross multiply
3y=18*4
3y=72
divide both sides by 3
y=24

24 yew trees