Answer:
140 in
Step-by-step explanation:
To find the volume use the formula length x width x height
2 x 10 x 7= 140 in
To find the surface area, you need to do the following:
A side of the figure is a trapezoid, so you should do 13+5x7 (since there are 2 of the same sides there is no need to divide by two.) and it should equal 126. To find the area of the top of the figure, you need to do 5x2 which equals 10. The area of the bottom of the figure is 26 (13x2), then do 2x3x2 to get the sides on the left and right of the figure. After all of this, add them together. (126+10+26+12=174.)
The surface area should be 174mm.
For this case we must raise the equation according to the given statement.
Let the variable "x" be the unknown number.
So, three times the number is: 
If to that term is added "6" we have:
The sum of both terms is "12", then:
Thus, the equation is:
Answer:
The cost of one book = $ 6 7
Number of books = 1 0 2
The cost of 102 books = $ 67 × 102
= $ 6834
Therefore, cost of 102 books = $ 6834
