2) A car travels 3/20 liters of gasoline for 3/4 kilometers, with an average of 1.5 liters of gasoline, and it can travel (5 kilometers) with an average of 1 liter of gasoline.

3) The circumference of a rectangle is 20cm, and the length-width ratio is 3:2. The area of this rectangle is (24) cm2.

4) 2/3 of A and 3/4 of B are equal (A and B are not 0), then B:A=( 2/3):( 3/4) (the answer is not unique).

application problem

1) a color TV is now 1020 yuan each, which is 3/20 lower than the original price. What is the original price? 1020/(1-3/20) =1200 yuan

2) According to the ratio of 1: 1000, the pesticide is 0.5 kg. How much water should I add? 1020/(1-3/20) =1200 yuan

3) The ratio of read pages to unread pages of a book is 1:4. After reading 30 pages, the ratio of read pages to unread pages is 4: 1. How many pages are there in this book? 30/(4/5- 1/5)=50 pages

Multiple choice

1) There are more students in Class A than Class B 1/5, and Class B is Class A (C).

A 1/6 B4/5 C5/6 D6/5

2) A bag of rice weighs 50 kilograms. If you eat 3/5, it will increase by 2/5. This bag of rice now weighs 28 pounds.

A50 B42 C36 D 12

T is right and F is wrong.

1) Dissolve 25g of salt in100g of water, and the salt content of this brine is 25%. F

2) The ratio of three sides of a triangle is 5:6:7, and the circumference is 54 decimeters. The lengths of the three sides of this triangle are 15 decimeter, 18 decimeter and 2 1 decimeter respectively. T

3)5m 1/7 is as long as 5/7 of1m. T

4) The product of two numbers is 1, and the two numbers are reciprocal. T

5) The number of boys is 2/5 of the number of girls, so the number of girls is 5/7 of the class.