Question 830991
How many 2-digit numbers less than 60 are even?
<pre>
I'll show you two ways.

The way you do this depends on whether you are studying
arithmetic sequences or not.  If you are not, then do
it this way:

The smallest is 20 and the largest is 58

Those numbers go like this: 

               20,22,24,...,54,56,58

The numbers that are halves of those numbers go like this

               10,11,12,...,27,28,29

The numbers that are 9 less than those numbers go like this

               1 , 2, 3,...,18,19,20

Answer: 20.

-------------------

If you are taking algebra and studying arithmetic sequences, then
do it this way:

a<sub>n</sub> = a<sub>1</sub> + (n-1)d

a<sub>n</sub> = 58, a<sub>1</sub> = 20, d=2

58 = 20 + (n-1)(2)

38 = 2(n-1)

Divide both sides by 2

19 = n-1

20 = n

Answer = 20.

Edwin</pre>