Money with Nathan in his savings account = $40
Rate of interest per annum = 5%
We know that :
In this case :
Principal = $40
Rate = 5%
Time = 1 year
Simple interest he will earn in 1 year :
Amount = Principal + Interest
Amount Nathan has to pay at the end of one year :
Thus, at the end of 1 year Nathan has to pay $42.
Therefore, simple interest Nathan will earn in 1 year = $2
Explanation
The question requires that we figure out the sides that represent the top/bottom faces and the left/right faces.
We are given the plan of the aluminum sheet
The top, bottom, left and right faces are shown below
The dimension for the top and bottom is
Since they are two
Therefore the total area for the top and bottom will be
For the left and right faces, the dimensions are
The dimensions of the left and right faces will be
Since they are two, then
The area will be
