A math problem in the senior high school entrance examination, add it when you are ready.

Now that you have calculated that the speed is 2 or 1.6,

I told you how to exclude 1.6.

Let the speed be v and the moving time be t.

From the meaning of the question: △OPQ bottom OQ=VT+2

The height can be expressed as (10-VT/2).

So the area can be expressed as:

s△OPQ = 1/2(VT+2)( 10-VT/2)

=-1/4 (vt) ˇ 2+9/2 (vt)+10 (process omitted)

Since v is a fixed value, it is considered a constant.

So when the area is the largest,

T=-b/2a=9/V (process omitted)

According to the image, when the area is the largest, t < 5.

Bring V=2 and V= 1.6 into T=9/V, respectively.

Available: when V= 1.6, t > 5, it should be discarded.

(2 stands for square)