Answer:
*37.5 liters of real fruit juice would be needed to produce 150 liters of Drink A
*10 liters of real fruit juice would be needed to produce 200 liters of Drink B
*0.25a liters of real fruit juice would be needed to produce a liters of Drink A
*0.05b liters of real fruit juice would be needed to produce b liters of Drink B
Step-by-step explanation:
If Drink A contains 25% of real fruit juice, to make 150 liters of Drink A we will need the below liters of real fruit juice;

If Drink B contains 5% of real fruit juice, to make 200 liters of Drink B we will need the below liters of real fruit juice;

a liters of Drink A will need the below amount of real fruit juice;

b liters of Drink B will need the below amount of real fruit juice;
