Acid–water ratio becomes 2:5:\nA beaker has acid:water = 1:x. When 300 ml of this mixture is mixed with 50 ml water (only), the new ratio is 2:5. Find x.

Introduction / Context:
Start from a mixture with acid:water = 1:x. Taking 300 ml preserves the ratio inside that sample. Then 50 ml pure water is added; set up the new ratio.

Given Data / Assumptions:

• Initial acid:water = 1:x.
• From that, 300 ml is taken: acid = 300*(1/(1+x)); water = 300*(x/(1+x)).
• Add 50 ml water.

Concept / Approach:
New mixture components: acid stays the same; water increases by 50 ml. New ratio = 2:5.

Step-by-Step Solution:

Recheck:
Wait: plugging x=2 gives A = 100; W = 200 + 50 = 250 → 100:250 = 2:5 (works). Option A shows 2, but the original set lists 4 as a candidate too. Correct is x = 2.

Why Other Options Are Wrong:
1, 3, 4 do not satisfy the derived proportion with the 50 ml extra water.

Common Pitfalls:
Forgetting the added water is pure water, not mixture.

Final Answer:
2