Draw a rectangle with a circumference of 20cm and a width of 2/3 of the length in the box below, and then divide the drawn rectangle into two rectangles with an area ratio of 1: 2.

Length of rectangle =20

First draw a rectangle with a length of 6 cm and a width of 4 cm; Then divide this rectangle into two rectangles: 2 cm long, 4 cm wide and 4 cm long and 4 cm wide. Fifth, solve the problem. (***30 points)

1. World Shipping 120 cases of mineral water, iced black tea is more than mineral water 1/3 cases. How many boxes of iced black tea were shipped?

120x (1+1/3) =160 cases A: (omitted)

2. There are 75 students in the big class and the middle class in Guangming Kindergarten, including 3/5 students in the big class. How many students are in the middle class?

75X( 1-3/5)=30 people A: (omitted)

5. A steel bar is 5/8 meters long. It was used for 2/7 meters for the first time, and a part of it was used for the second time, leaving the full length of 1/4. How many meters are left?

5/8x 1/4 = 5/32m A: (omitted)

Wang Qian: I wrote 48 articles on my blog. Ji Hui: I'm seven-eighths of Wang Qian. Zhang Wei: My blog posts are 2/7 more than Ji Hui's. Do you know how many articles Ji Hui and Zhang Wei have written on their blogs?

48X7/8X( 1+2/7)=54 articles.

Sixth, thinking expansion. (***20 points)

1. The average height of grade one students in a school is 1 15cm, in which boys are taller than girls 1/5 and girls are taller than boys110. What is the average height of boys in this grade?

Because there are more boys than girls 1/5, the ratio of boys to girls is (1+1/5):1= 6: 5.

If the boy's height is x cm, the girl's height is (1+110) x cm.

According to the total height, the total number = average height.

[6X+5×( 1+ 1/ 10)X]=(6+5)= 1 15 X = 1 10

Two brothers buy a villa together. The eldest brother contributed 500,000 yuan, the second brother contributed 65,438+0.2 of the total amount of the other two brothers, and the third brother contributed 65,438+0.3 of the total amount of the other two brothers. How much is this villa?

Analysis: The contribution of the second brother is 1/2 of the total amount of the other two brothers, that is,11+2 of the total amount of the villa (that is, 1/3).

The contribution of the third brother is 1/3 of the total amount of the other two brothers, that is,11+3 of the total amount of the villa (that is, 1/4).

According to the amount of money given by the boss, the percentage of the boss in the total villa = the total villa formula.

50 ÷ ( 1- 1/ 1+2 - 1/ 1+3)

=50÷5/ 12

= 65438+200,000 yuan