Solving linear systems: pls help me its due soon!!!

the pythagoras juice company produces twwo types of enegry-boosting juices: the "strong" variety, which is 78% pulp juice, and the "weak" variety, which is only 32% pulp juice.

natasha prefers a "middle ground" -54% pulp juice, if she wants to fill a 450ml bottle with "middle ground juice", how much "strong" or "weak" juice will she need? solve using linear equations