1. The problem states that there are 15 houses on Mr. Sullivan's street, so I drew a picture of them2. Pick a starting point. I always like to start at the beginning so I don't get confused, so I'll pick house no. 1. If Mr. Sullivan lives in house 1, then the total I get by adding the house numbers before his = 0. There are no house in front. I cannot add together any house numbers after his and get the answer of 0; therefore, Mr. Sullivan cannot live in house 1.
4. Now I try house no. 3. The total by adding the house numbers before his is 3. 1+2=3. I cannot get a sum of 3 by adding the houses after his, so he cannot live in house no. 3.
5. I try house no. 4. The total of the house numbers before his is now 6. The sum of the next 2 houses after his is 11 (5+6=11). He does not live in house number 4.
6. I try house no. 5. Once again the sum of the houses before his does not equal the sum of the houses after his.
7. Now I try house no. 6. The sum of the houses before his is 15 (1+2+3+4+5=15). The sum of the next 2 houses after his is 15 (7+8=15). EGAD! I have found the answer. Mr. Sullivan lives in house number six. But wait! The question does not ask for his house number, but for the number of houses on the street. Since I added house numbers 7 and 8 together, I know that the last house on the street is number 8. There are 8 houses on Mr. Sullivan's street.
Now to this week's hint:
1. Find the amount that Ryan paid.
2. If the magazine costs twice as much as the book, it counts as 2 portions of the cost. There are 3 books which make up 3 portions of the cost. Together they make up 5 portions of the cost.