Introduce useful notation
Name stuff.
A = # of marbles for Ali
B = # of marbles for Bala
C = # of marbles for Calvin
Now, start translating those sentences.
Let's see what you get.
3 boys have 656 marbles.
Ali has 3 times more marbles than Bala.
Calvin has 34 few than Bala.
How many marbles does Bala have?