Answer:
Part A)
The number of marbles that Su has at the beginning is 
The number of marbles that Bertha has at the beginning is 
Part B)
The number of marbles that Su has at the end is 
The number of marbles that Bertha has at the end is 
Step-by-step explanation:
Let
x------> number of marbles that Su has at the beginning
y------> number of marbles that Bertha has at the beginning
we know that
----> equation A
----> equation B
substitute equation A in equation B



Find the value of x

Part A) How many marbles did they EACH have at the begining?
The number of marbles that Su has at the beginning is 
The number of marbles that Bertha has at the beginning is 
Part B) How many did they EACH have at the end?

so


therefore
The number of marbles that Su has at the end is 
The number of marbles that Bertha has at the end is 