(Average Problem) Question: The average of x1 x2 x3 and x4 is 16. Half the sum of x2 x3 x4 is 23. What is the value of x1?
(1) 18 (2) 19 (3) 20 (4) 17
Solution :
(x1 + x2 + x3 + x4 )/4 = 16
X1 + x2 + x3 + xe = 16 * 4 = 64
½( x2 + x3 + x4 ) = 23
x2 + x3 + x4 = 23 * 2 = 46
x1 + 46 = 64
x1 = 64 – 46 = 18 !!