SAT Mathematics Practice Test 5

If $2.5$ ounces of chocolate are needed for each muffin, then the number of ounces of chocolate needed to make 48 muffins is $48\times 2.5=120$ ounces. Since 1 pound = 16 ounces, the number of pounds that is equivalent to $120$ ounces is $\frac{120}{16}=7.5$ pounds.Therefore, 7.5 pounds of chocolate are needed to make the 48 muffins.
Choice B is incorrect. If 10 pounds of chocolate were needed to make 48 muffins, then the total number of ounces of chocolate needed would be $10\times 16=160$ ounces. The number of ounces of chocolate per muffin would then be $\frac{160}{48}=3.33$ ounces per muffin,not $2.5$ ounces per muffin. Choices C and D are also incorrect. Following the same procedures as used to test choice B gives $16.8$ ounces per muffin for choice C and $40$ ounces per muffin for choice D, not $2.5$ ounces per muffin. Therefore, $50.5$ and $120$ pounds cannot be the number of pounds needed to make 48 signature chocolate muffins.