Last year, for every 100 million vehicles that traveled on a certain highway, 100 vehicles were involved in accidents. If 2 billion vehicles traveled on the highway last year, how many of those vehicles were involved in accidents? (1 billion = 1,000,000,000)	Choose the correct option
A) 500 B) 1500 C) 2500 D) 2000 E) 1000

Rationale: "to solve we will set up a proportion . we know that “ 100 million vehicles is to 100 accidents as 2 billion vehicles is to x accidents ” . to express everything in terms of “ millions ” , we can use 2,000 million rather than 2 billion . creating a proportion we have : 100 / 100 = 2,000 / x cross multiplying gives us : 100 x = 2,000 * 100 x = 20 * 100 = 2000 answer : d"
Answer: D