Correct Answer: B

Rationale: To convert 6 feet to inches, we multiply 6 by 12 (1 foot = 12 inches), giving us 72 inches needed. By adding the lengths of the two ropes (40 inches + 36 inches), Jeff would have a total of 76 inches, which is more than the 72 inches required. Therefore, he would have enough rope if he ties them together. Choice A and D are incorrect because they misinterpret the conversion from feet to inches. Choice C is incorrect as it does not consider the actual combined length of the two ropes.

Correct Answer: D

Rationale: To convert kilograms to pounds, you multiply the weight in kilograms by 2.20462. Therefore, to convert 45 kg to pounds, you would perform the calculation: 45 kg * 2.20462 = 99.2079 pounds. Rounding to the nearest whole number, the answer is approximately 110 pounds. Choice A (10 pounds) is incorrect as it is too low. Choice B (100 pounds) and Choice C (1,000 pounds) are also incorrect as they are too high. The correct conversion is closest to Choice D (110 pounds).

Correct Answer: B

Rationale: To convert meters to millimeters, you need to know that there are 1000 millimeters in 1 meter. Therefore, to find out how many millimeters are in 4 meters, you multiply 4 (meters) by 1000 (millimeters per meter), which equals 4000 millimeters. Choice A, 400 mm, is incorrect because it represents 4 decimeters, not 4 meters. Choice C, 40 mm, is incorrect because it represents 4 centimeters, not 4 meters. Choice D, 100 mm, is incorrect because it represents 1 meter, not 4 meters.

Correct Answer: C

Rationale: To find the flow rate in drops per minute, first, calculate the total volume in drops by multiplying the volume in milliliters by the number of drops per milliliter (500ml * 20 drops/ml = 10,000 drops). Then, divide this total number of drops by the infusion time in minutes (4 hours * 60 minutes/hour = 240 minutes) to get the flow rate. Therefore, the correct flow rate is 50 drops/min. Choice A is incorrect because it miscalculates the flow rate. Choice B is incorrect as it also miscalculates the flow rate. Choice D is incorrect as it overestimates the flow rate.

Correct Answer: B

Rationale: To calculate the percentage of her earnings that Jill saved, divide the amount saved ($140) by the total earnings ($400) and then multiply by 100 to find the percentage. Therefore, (140/400) * 100 = 35%. Jill saved 35% of her earnings. Choice A (30%) is incorrect because it underestimates the percentage saved. Choice C (40%) is incorrect as it overestimates the percentage saved. Choice D (25%) is incorrect for the same reason. The correct calculation is 140/400 = 0.35 * 100 = 35%.