Jinglander wrote:

A company sells pens and pencils. The Revenue from pens in 2007 was up 5% from 2006. The revenue from pencils declined 13% over the same period. Overall revenue was down 1% from 06 to 07. What was the ratio of pencil revenue to pen revenue in 2006.

forgot about percentage and change into numericals.

in 2006 the price of pen and pencil both are 100. so the total average of revenue is 100 too.

in 2007 the price of pen is 105 and pencil is 87. As it was mentioned in question average slipped by 1 point so 99.

6 12

105-------99--------------87

the ratio will be 12:6 of pen to pencil ratio. i.e., 2:1

but, it was asked for pencil to pen so it is 1:2...

this is one of the best method you can try for all mixture problems.