Experience the Quality With Free DAT Exam Questions That Helps Candidates Pass

The passage states xerostomia causes difficulty swallowing and increases caries and infection risk. Option A relates to periodontitis, B is opposite of xerostomia, and D is unrelated. On DAT RC, always tie the answer directly to text.

Let x = original. After a 25% increase: 1.25x = 50 → x = 50 ÷ 1.25 = 40. Option C is correct. On DAT QR, percentage increase problems require setting up proper proportion equations.

Let xx be the volume (mL) of 20% solution, mixed with (500−x)(500 - x) mL of water (0% solute). The mass (or equivalent) of solute contributed is 0.20x0.20x grams per 100 mL, but percentage math works directly with volumes here since both sides are in mL and percent (w/v). The target solution contains 0.12×500=600.12 \times 500 = 60 units of solute (e.g., grams per 100 mL scaling). Set 0.20x=60⇒x=300 mL0.20x = 60 \Rightarrow x = 300\ \text{mL}. Options A and B underdeliver solute, producing ≤12% when diluted to 500 mL, while D overshoots the required solute mass, exceeding 12%. A quick check: 300 mL of 20% contains 60 units; adding 200 mL water totals 500 mL with 60/500 = 12%. On the DAT, set up mixture equations by equating total solute before and after mixing, and remember that adding pure solvent scales volume but not solute amount—keeping the calculation straightforward.

Strong oxidizers like KMnO₄ and CrO₃ convert primary alcohols fully to carboxylic acids. PCC (A) stops at aldehydes. NaBH₄ and LiAlH₄ (C, D) are reducing agents. DAT organic requires differentiating mild vs strong oxidizing reagents.

4x − 7 = 13 → 4x = 20 → x = 5. Thus Option C. DAT QR frequently tests linear equations; accuracy in rearranging terms is critical.