The average length of 6 snakes is 80 cm. If the average length of one third of the snakes is 70 cm, what is the average of the other snakes? Choose the correct option:
A) 75.
B) 85.
C) 90
D) 94
E) 100
Given ( X1 + X2 ... + X6 ) / 6 = 80   ( X1 + X2 ... + X6 ) = 480 --&gt; Eq 1.   Now given avg length of one third snakes is 70. That means out  6 / 3= 
<gadget id="calculator"> 6 / 3</gadget>
<output>2</output>
2 snakes.   let the avg length of two snakes 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 snakes.   Answer: correct option is 85..
<result>B</result>
The average length of 6 snakes is 80 cm. If the average length of one third of the snakes is 70 cm, what is the average of the other snakes?