Answer:
<em>1710 trees up to 2016 (not including 2016)</em>
<em>2100 trees up to 2016 (including 2016)</em>
Step-by-step explanation:
Given that
Farm started with 30 trees in 2007.
Every year 40 more trees than the previous year.
It is actually an Arithmetic Progression (AP) with
First term, a = 30 and
Common Difference, d = 40
The AP will look like:
30, 70, 110, 150, ....
We have to find the sum of this AP upto 9 terms and 10 terms:
9 terms sum will give us the total number of trees up to 2016 (not including 2016).
10 terms sum will give us the total number of trees up to 2016 (including 2016).
Formula for sum of 'n' terms of an AP:
<em>1710 trees up to 2016 (not including 2016)</em>
<em>2100 trees up to 2016 (including 2016)</em>