X - the number of pencils
y - the number of pens
She has twice as many pencils as she has pens.
Tom borrows a pen, so she has y-1 pens. Now she has ten less pens than pencils.
Set 2y and y+9 equal to each other:
She has 9 pens.
Euclidean geometry is all about shapes, lines, and angles and how they interact with each other. There is a lot of work that must be done in the beginning to learn the language of geometry. Once you have learned the basic postulates and the properties of all the shapes and lines, you can begin to use this information to solve geometry problems. Unfortunately, geometry takes time, but if you put in the effort, you can understand it.
Year New flowers
1 1200
2 300
3 75
There were 1200 wildflowers in the first year that the park started tracking them. Since then, there have been one fourth as many new flowers each year
Initially there are 1200 flowers and start decreasing by 
So first term is 1200 and common ratio is .
Its a geometric sequence so summation becomes
i =1∑ ∞ 1200(
Now we find the sum
We use sum formula
Where a is the first term , a= 1200
r is the common ratio , r= 1/4
Sum = 1600 wildflowers
Part A: 6.2
Part B:6.405
PArt C: The estimate was close to the real answer
