a. How many floors are between the seventh and fifteenth floors?
3 odd integers have a property that they average up to the middle large one. Let's say we have 3, 5, and 7. 3 is 2 less than 5 and 7 is 2 more than 5. so when you add them it equals 2 times 5.
After we know that, the sum of 3 odd integers is just 3 times the middle number. ex. 3+5+7 = 3 times 5 = 15
Then we know the some number times three = 225. we find out that the middle number is 75, so the other two are 73 and 77
