Q33:

At a certain school, the ratio of the number of second graders to the number of fourth graders is 8 to 5, and the ratio of the number of first graders to the number of second graders is 3 to 4. If the ratio of the number of third graders to the number of fourth graders is 3 to 2, what is the ratio of the number of first graders to the number of third graders?

B. 9 to 5

C. 5 to 16

D. 5 to 4

E. 4 to 5

请问这题怎么做?谢谢!!

a2/a4=8/5/=4/2.5

a1/a2=3/4这两个合起来得,a1/a4=3/2.5;

再由a3/a4=3/2然后在合刚才求出得式子向除,得E.