Number of Adults = a
Number of children = 2a
Number of people in a group = 45
so
a + 2a = 45
3a = 45
a = 15
Number of Adults = 15
Number of children = 30
I believe the answer is d, because i cant find a pattern where x and y are directly connected.
Answer:
I'm not totally sure what your asking but it should be 6.9 cups
I'm assuming ya want us to simplify 
reemember some exponential rules


so



