There are 300 students going for an outing and buying water. Now there is a special offer, buy 5 bottles of water to send 1 bottle. Calculate how many bottles of water you actually need to buy. Suppose the actual number of bottles to be purchased is X bottles. According to the preferential activities, for every five bottles of water you buy, you get six bottles of water (because you got one). You only need to pay the price of 5 bottles for every 6 bottles of water. Divide the total number of bottles needed by 300 students by 6, and the quotient is the number of groups that need to be purchased at the price of 5 bottles. Each group needs to buy 5 bottles, and the total number of bottles purchased is the number of groups multiplied by 5.

Use a mathematical formula, expressed as: x = (300 // 6) × 5. Now, calculate the value of x. The calculation result is: actually need to buy 250 bottles of water.