Digital PSAT Math Practice Question 189: Answer and Explanation

Question: 189

How many more kilograms (to the nearest hundredth) will a 2 cubic meter balloon that is filled with air weigh than an identical balloon that is filled with helium, given that helium has a density of and air has a density of ?

• A. 0.21
• B. 1.02
• C. 1.38
• D. 2.04

Correct Answer: D

Explanation:

(D) The weight of the balloon itself is irrelevant since the balloon is identical in both situations. 1.2 - 0.179 = 1.021 is the difference in density between the two balloons. Since you have a 2 cubic meter balloon, simply multiply 1.021 by 2 to give approximately 2.04.