The numbers a, b, and c are consecutive integers and 0 < a < b < c. If

i.e a and c are two consecutive Even Integers

Solution

• The units’ digit of \(c*a = 4\)

o It means at least one of a and c must be even number.
• Now, a, b, and c are consecutive integers.

o So, if a is even then c also must be even, and vice-versa.
o Thus, both a and c are consecutive even integers.
• As, \(0 < a < b < c \)

o This implies that \(a < c\)
o So, possible values of (unit’s digit of a, unit’s digit of c) are (0, 2), (2, 4), (4, 6), (6, 8) and (8, 0).
o Out of which only unit’s digit of \((4*6) = 4\)

 Thus, \((a, c)\) can be \((4, 6), (14, 16), (24, 26), (34, 36), ……, etc.\)
 Therefore, \((a, b, c)\) can be \((4, 5, 6), (14, 15, 16), (24, 25, 26),……, etc.\)

• In all the cases, unit’s digit of b = 5.