The sum of 3 consecutive integers is 30. What is the least of these integers?

Let
n
be the smallest of the three consecutive numbers
→
the other two numbers are
n
+
1
and
n
+
2
We are told
XXX
(
n
)
+
(
n
+
1
)
+
(
n
+
2
)
=
30
→
XX
3
n
+
3
=
30
→
XX
3
n
=
27
→
XX
n
=
9

The three numbers are 9, 10, and 11. We can define an even number as
2
x
Let
2
x
be the first even number
Let
2
x
+
2
be the next even number
Let
2
x
+
4
be the last one
Their sum is
30
so we write
2
x
+
(
2
x
+
2
)
+
(
2
x
+
4
)
=
30
Combining like terms
6
x
+
6
=
30
6
x
=
24
x
=
4
So
2
x
=
2
(
4
)
=
8
2
x
+
2
=
8
+
2
=
10
2
x
+
4
=
8
+
4
=
12