Digital PSAT Math Practice Question 87: Answer and Explanation

Question: 87

Light travels at approximately 3.00 × 10⁸ meters per second. When the planet Jupiter is at its closest point to Earth, it is 588 million kilometers away. When Earth and Jupiter are this close, approximately how many minutes does light reflected off of Jupiter take to reach Earth?

• A. 3 minutes
• B. 33 minutes
• C. 58 minutes
• D. 18 minutes

Correct Answer: B

Explanation:

(B) Let's first convert 588 million kilometers to meters:

Because distance = rate × time, it follows that . Therefore, the t in seconds is given by the following expression:

Because there are 60 seconds in every minute,

This answer rounds to 33 minutes, which is choice (B).