3 1+ 13-40=4

At least four people answered three questions correctly.

2. White (last name)

Because skin color is different from clothes color, it is definitely not yellow.

Mr. Black is not wearing white clothes.

So, Mr. Black skin must be yellow skin.

Then Mr. White must be black.

So, the rest, Mr. Yellow skin is white.

3、 12000( 100×5×4×3×2)

The fifth number is less than 100.

So the fourth number is less than 100×5=500.

The third number is less than 500×4=2000.

The second number is less than 2000×3=6000.

The first number is less than 6000×2= 12000.

4. The number of people who can sit in each row = the number of seats /2, and then rounded (that is, divided by 2, one decimal place will be entered).

There are 20 seats in the first row, which can take 20/2= 10 people.

The second row can take 2 1/2, and one person can enter, 1 1.

The third row can seat 22/2= 1 1 person.

There are 23/2 seats in the fourth row, and one person can enter. 12 people.

……

There can be 39/2 seats in the 20th row, one can go in, and there are 20 people.

Gundam10+11+1+12+12+...+19+/kloc-0 = 60.

5. Add the three numbers and divide by 2 to get the total weight of the three boxes:

(63+65+66)/2=97

The heaviest 97-63=34 kg.

Lightest 97-66=3 1 kg

34-3 1=3 kg

6. Apricot× (1-3/5) = peach -30= pear+15

Set up x pear trees

Peach tree =x+ 15+30=x+45.

Apricot tree = (x+15) ÷ (1-3/5) = (5/2) x+75/2.

Add the three: x+x+45+(5/2)x+75/2= 1500.

Solution, x=3 15

Pear 3 15, peach 3 15+45 = apricot 360+0500-3 15-360 = apricot 825.