From the statement of the problem, we know that.
• Andrea lives 5 1/2 blocks to the west of school → x = -5.5,
,
• Ben lives 4 blocks to the east of school → x = +4,
,
• Christine lives 2 blocks to the west of school → x = -2,
,
• Doug lives 6 1/2 blocks to the east of school → x = +6.5.
A) Using the data above, we have:
B) The x coordinate of:
• Andrea is x_A = -5.5,
,
• Ben is x_B = +4.
The distance between Ben and Andrea is equal to the difference between its coordinates:
We find that Ben lives 9.5 blocks from Andrea.