If we assume that
x isthe number of multiple choice questions, and y is the number of word problems, we can write a system of equations like:
{ x + y = 38
{ 2x + 5y = 100
If we multiply the first equation by -2 we get:
{ -2x-2y = -76
{ 2x + 5y = 100
Now if we add both equations we get only equation with 1 unknown (y) :
3y = 24 ⇒ y = 8
Substituting the calculated value to the first equation we get:
x + 8 = 38 ⇒ x = 30
The solution:
{ x = 30
{ y = 8
means that:
The test had 30 multiple choice questions, and 8 word problems.
The answer would be B. (228-89) because you are trying to find the difference.
For this case, what you must do is take out the area of two triangles and add it to the area of a rectangle to find the total area.
We have then:
Triangle area:
A = (1/2) * ((13-9) / (2)) * (10) = 10 in ^ 2
Rectangle area:
A = (9) * (10) = 90 in ^ 2
Total area:
At = 2 * (10) + 90 = 110 in ^ 2
answer:
110 in²
