Answer:
1000/400=2.5
2.5×200=500 units
Explanation:
1000 is the price, the price of 1000 has to divided into 400 units to get 1 unit value to 2.5 dollar. If u got 200 unit, u have to times 2.5 dollar, imagine if 1 unit got 2.5 dollar, then u how many units u have to times to get the cost?