Of the four numbers, whose average is 100, the first is one-fourth of the sum of the last three. The first number is ? Select the correct option:	A) 28	B) 29	C) 80	D) 48	E) 10
Explanation:   Let the first number be x,   Then, sum of the four numbers = x + 4x = 5x.   so, 5x/4 = 100 or x = (100 * 4) / 5= 
<gadget id="calculator">(100 * 4) / 5</gadget>
<output>80</output>
80   Answer: 80
<result>C</result>
Of the four numbers, whose average is 100, the first is one-fourth of the sum of the last three. The first number is ?