There are 4 people of different heights standing in order of increasing height. The difference is 2 inches between the first person and the second person, and also between the second person and the third person. The difference between the third person and the fourth person is 6 inches and the average height is 78. How tall is the fourth person?
Choose the correct choice from the following options:
A) 82
B) 84
C) 86
D) 88
E) 90
Let x be the height of the first person.   Then the heights are x, x+2, x+4, and x+10.   4x+16 = 4(78) = 312   x = 74 and the fourth person has a height of 74+10= 
<gadget id="calculator">74+10</gadget>
<output>84</output>
84 inches   The answer is 84.
<result>B</result>
There are 4 people of different heights standing in order of increasing height. The difference is 2 inches between the first person and the second person, and also between the second person and the third person. The difference between the third person and the fourth person is 6 inches and the average height is 78. How tall is the fourth person?