Answer:
We conclude that he purchased 20 rookie cards and 8 Hall of Fame cards.
Step-by-step explanation:
We know that Connor spent $66 on rookie cards and Hall of Fame cards. We know that rookie cards are four for six Hall of Fame two for nine.
Therefore, we calculate:

5·4= 20 rookie cards
4·2= 8 Hall of Fame cards
We conclude that he purchased 20 rookie cards and 8 Hall of Fame cards.
Answer:
3
Step-by-step explanation:
It would be 56/177. If you need any question how I got that answer, ask me.. :)
Your answer would be 3/4 = 15/20 = 75/100
Now their are two ways to figure out this problem.
You can look at the relationship with 3 and 15. 3 x 5 is 15 so you can determine that something x 5 equals 20. Well 20 x 5 = 4 so your answer is 3/4.
You would then do the same thing with 15/20.
20 x 5= 100, so do 15 x 5 which is 75. Answer is 75/100
Now here is the 2nd way you could have done it.
well we know that 3/4 equals .75 and that equals 75/100 as a fraction. Then divide top and bottom by 5 to get 15/20.