For this case, we have the following expression:

We simplify the expression:
If we add similar terms, taking into account that different signs are subtracted and the sign of the greater one is placed, we have that 
So, we have to:

Answer:
-3x + x + 5 = -2x + 5
Number of cartons taken:

ratio of cartons taken : ratio of total cartons
73 : 100
The answer is 12.1, add both 4.5 and 7.6 and you get 12.1
I'll meet you at the corner is the answer to this riddle.