a, b, c are distinct numbers and the HCF of each pair of numbers (13, a), (13, b), (13, c) is 13, where a, b, c are each less than 60 and a < b < c. What is the value of \(\frac{a\;+\;c}{b}\)?

3.5 4.5 2 5

2

13, 26, 39, 52 < less than 60, Therefore, a = 26 b = 39 c = 52 ⇒ \(\frac{a + c}{b}\) = \(\frac{78}{39}\) = 2