Common Core: S-CP.8
Problem 23 of 45s12-023
At a school, 40% of students ride the bus. Of bus riders, 15% arrive late; of the others, 5% arrive late. What is the probability a random student rides the bus and arrives late?
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Solution walkthrough1:49
- Both must happen, and lateness depends on the bus. Use .
- From the question: , and "of bus riders, 15%" means .
- Multiply: . It is fifteen percent of the bus strip.
- Check with students: ride the bus, of is , and .
- Traps: is only among bus riders, is every late student, and adds instead of multiplying.