Answer:
Sequence: 13, 20, 27
Rule: Tn = 7n + 6
Explanation:
The 3 other numbers that can form an arithmetic progression is 13, 20, 27...
The nth term of an arithmetic progression is expressed as;
Tn = a + (n-1)d
a is the first term = 13
n is the number of terms
d is the common difference = 20 - 13 = 27 - 20
d = 7
Substitute
Tn = 13 + (n-1)(7)
Tn = 13 + 7n - 7
Tn = 7n+13-7
Tn = 7n + 6
This gives the required rule