Last year, for every 100 million vehicles that traveled on a certain highway, 80 vehicles were involved in accidents. If 4 billion vehicles traveled on the highway last year, how many of those vehicles were involved in accidents? (1 billion = 1,000,000,000)  Answers: A) 1600 B) 3200 C) 800 D) 400 E) 200

Rationale: "to solve we will set up a proportion . we know that “ 100 million vehicles is to 80 accidents as 4 billion vehicles is to x accidents ” . to express everything in terms of “ millions ” , we can use 4,000 million rather than 4 billion . creating a proportion we have : 100 / 80 = 4,000 / x cross multiplying gives us : 100 x = 4,000 * 80 x = 40 * 80 = 3200 answer : b"
Answer: B