Brain Teasers & Mental Math
Estimate how many cars are sold (new) in the United States each year.
Model answer
Bottom-up via installed base and replacement. ~250M registered passenger vehicles in the US. Average vehicle lifespan ~12 years → steady-state replacement ≈ 250M / 12 ≈ ~21M/year. But not all…
The full, human-reviewed answer is in the bank.
Sign up free and Daily 10 serves you 10 questions a day from all 1,500+ — or go Pro for unlimited reps.
More from Brain Teasers & Mental Math
- You roll one fair six-sided die. What is the probability you roll a number greater than 4?
- Flip a fair coin twice. What is the probability of getting at least one head?
- Draw one card from a standard 52-card deck. What is the probability it is a face card (J, Q, or K)?
- Draw one card from a 52-card deck. What is the probability it is a heart OR a king?
- Roll two fair dice. What is the probability the two dice show the same number (a double)?
- A test for a disease is 99% accurate (99% sensitivity and 99% specificity). The disease affects 1 in 10,000 people. You test positive. What is the probability you actually have it?