6 wires are by average 80 cm long each. If the average length of one third of the wires is 70 cm, what is the average of the other wires?
Pick
A) 75.	B) 85.	C) 90.	D) 94.	E) 100.
Edit:   Given ( X1 + X2 ... + X6 ) / 6 = 80   ( X1 + X2 ... + X6 ) = 480 --&gt; Eq 1.   Now given avg length of one third wires is 70. That means out  6 / 3= 
<gadget id="calculator"> 6 / 3</gadget>
<output>2</output>
2 wires.   let the avg length of two wires be ( X1 + X2 ) / 2= 70 .   ( X1 + X2 ) = 140. --&gt; eq 2.   Now we are asked to find the average of the remaining i.e. ( X3 + X4 + X5 + X6 )   Substitute eq 2 in eq 1 then we get   140 + X3 + X4 + X5 + X6 = 480   =&gt; X3 + X4 + X5 + X6 = 340   Now divide 340 by 4 we get 85.   =&gt; ( X3 + X4 + X5 + X6) / 4 = 85 = avg length of remaining wires.   IMO correct option is 85..
<result>B</result>
6 wires are by average 80 cm long each. If the average length of one third of the wires is 70 cm, what is the average of the other wires?