How many U.S. states share a border with Mexico?
4
13
13
13
13
13
13
13
13
13
13
10
13
12
21
14
10
13
5
12
21
14
10
13
5
12
21
14
10
9
13
5
12
21
14
11
10
9
13
5
12
21
14
11
10
9
7
13
5
12
21
14
11
8
10
9
7
13
5
12
21
14
11
8
10
9
7
13
5
12
21
14
11
8
10
15
9
7
13
5
12
21
14
11
31
8
26
10
15
9
7
2
13
5
12
21
1
29
14
11
31
4
8
26
10
15
9
7
2
5
12
21
1
29
27
14
11
31
4
8
26
10
20
15
9
7
2
28
5
12
21
1
29
27
14
11
31
4
8
26
3
10
20
49
15
9
7
2
13 states
28
5
12
21
1
29
27
14
11
31
4
8
26
3
10
20
49
15
9
34
7
2
25
28
5
12
21
1
29
27
14
11
31
4
8
26
3
10
20
49
15
9
34
7
2
25
28
5
12
21
1
29