2) In a pack of construction paper the number of blue and red sheets
are originally in the ratio 2:7.
Each day, a gril uses 1 blue and 3 red sheets.
One day she uses 3 red sheets and the last blue sheet.
At this time there are 15 red remaining.
How many sheets of paper were in the pack originally?
Let = number of blue sheets.
Let = number of red sheets.
. . Hence, the pack contains sheets.
During the next days, she takes blue and red sheets.
Then the number of remaining sheets are: .
But we are told that the remaining sheets are: .
We have a system of equations: .
. . with the solution: .
Therefore, there were: . sheets originally.