Answer:the need to buy 3600 pencils.
Step-by-step explanation:
In 2005 the city agency spent $2000 to buy pencils at a cost of $5 a dozen. This means that the number of dozens of pencil that they bought in 2005 is
2000/5 = 400
There are 12 pencils in a dozen. Therefore, total number of pencils that they bought in 2005 is
400 × 12 = 4800 pencils
if the agency used 3/4 of these pencils in 2005, it means that the number of pencils that they used in 2005 is
3/4 × 4800 = 3600
The number of pencils left is
4800 - 3600 = 1200 pencils
If they use the same number of pencils in 2006, then the number of pencils that they have to buy is
4800 - 1200 = 3600 pencils