The amount available is potassium chloride liquid 40 mEq/15 mL. How many mL should the nurse administer? (Round the answer to the nearest tenth. Use a leading zero if it applies. Do not use a trailing zero.)

Step 1 sets up the equation: (20 mEq ÷ 40 mEq) × 15 mL. Step 2 is to perform the division: 0.5 × 15 mL. Step 3 is to perform the multiplication: of 7.5 mL. So, the correct answer is 7.5 mL.