Use this tax table to find how much tax you need to pay on a taxable income of $40,000.
If taxable
income is over-
The tax is:
But not
over-
SO
S7,825
$31,850
$77,100
$7,825 10 percent of the
amount over SO
S31.850 $782.50 plus 15 percent
of the amount over
7,825
$77,100 S4,386.25 plus 25
percent of the amount
over 31,850
$160,850 $15,698.75 plus 28
percent of the amount
over 77.100
$349,700 $39,148.75 plus 33
percent of the amount
over 160,850
$101,469.25 plus 35
percent of the amount
over 349,700
S160,850
$349,700
no limit
A.
$6,423.75
B.
$8,150.50
C.
$12,536.25

Explanation:

I think about the Golden Gate Bridge, which is a suspension bridge.

As in any suspension bridge, a long cable is supported by two large supports.

The cable falls from a support, in the form of a curve concave upwards, to a minimum point that is the vertex of the parabola, through which the axis of symmetry passes, and curves again upwards to ascend to the upper end of the other support.

As a unique feature of this parabolic arc you can tell that the the concavity is upward; the parabola open upward.

Also, you can tell that the parabola is vertical, which means that the axis of symmetry is vertical.

The symmetry is clear because to the curve to the left of the vertex is a mirror image of the curve to the right of the vertex.