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 75. How tall is the fourth person?
Answers
A) 73 B) 75 C) 77 D) 79 E) 81
Let x be the height of the first person.   Then the heights are x, x+2, x+4, and x+10.   4x+16 = 4(75) = 300   x = 71 and the fourth person has a height of 71+10= 
<gadget id="calculator">71+10</gadget>
<output>81</output>
81 inches   The answer is 81.
<result>E</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 75. How tall is the fourth person?