In a practical problem, if a car travels 60 km/h and a truck travels 40 km/h, how long will it take for both to meet if they start 200 km apart and travel towards each other?
A store sells pencils for $0.50 each and erasers for $0.75 each. If a student buys a total of 10 items for $6.00, how many pencils did the student buy?