# If the sum of the first #100# terms of an arithmetic series with common difference #9# is #20888#, what is the first term?

##### 1 Answer

Apr 10, 2017

#### Answer:

The first term is

#### Explanation:

We use the formula

#20888 = 100/2(2a + (100 - 1)9)#

Solving for

#20888 = 50(2a + 891)#

#20888 = 100a + 44550#

#-23662 = 100a#

#a = -236.62#

Hopefully this helps!