If the first term of an arithmetic sequence is 4 and the third term is 18, what is the 23rd term?
a.92
b.116
c.158
d.161

C. 158

1. term          2. term          3. term          4. term          5. term
 4                   4 + d          18=4+d+d             18 + d           18 + d + d 
                                        14=2d
                                          7=d
                     
The equation: 4 + 7(k - 1)
First term: 4 = 4 + 7(1 - 1) = 4
Third term: 18 = 4 + 7(3 - 1) = 18

23. term: 4 + 7.(23 - 1) = 4 + 7.22 = 158

Aand b are correctly balanced reactions. they have the same number of atoms in both sides of the reaction