Solution: Let the numerator be X and the denominator be (x+3).
According to the meaning of the question, "if the molecule subtracts 1, it can be about half."
(x- 1)/(x+3)= 1/2 is used for the column equation.
X=5, denominator is 5+3=8,
Then the simplest score is 5/8.
2. Multiply the numbers A and B. If A is increased by one third, the product will be increased by one fifteenth under the condition that the number of B remains unchanged. If b is increased by one fifth, the number of a remains the same and the product is increased by one fifteenth. What are the numbers of A and B respectively?
(This won't do, please refer to the upstairs.)
Let A be X and B be Y. According to the meaning of the topic (X+1/3), Y = XY+115 and Y = 1/5, the solution can be obtained. Then x (y+1/5) = xy+115 to calculate X= 1/3.
A clothing factory produced 4500 sets of sportswear in February, one tenth less than that in January. How many sets of clothes were produced in January?
Solution: suppose that x sets are generated in January, and the equation is obtained according to the meaning of the question.
X- 1/ 10X=4500
9/ 10X=4500
X=5000 (sets) a: omitted.
Fourth, fifth-grade students 198. 12.5% of boys and 18% of girls participated in the school table tennis training. There are exactly the same number of boys and girls left. How many boys and girls are there in Grade Five?
Solution: If the number of boys is x, the number of girls is 198-X, and the remaining number of boys is (1- 12.5%) X,
The remaining number of female students is 198-X- 18.
According to the meaning of the question, "there are exactly the same number of boys and girls left."
Column equation
( 1- 12.5%)X = 198-X- 18
87.5%X= 180-X
7/8X+X= 180
X=96 (person) 198-96= 102 (person)
A: 96 boys and 96 girls 102.
An iron ball is immersed in the water of a rectangular water tank. When the iron ball was taken out, the water level in the water tank dropped by 9 mm ... Another cube with a side length of 6cm was immersed in the water in the tank, and the water in the tank rose by12 mm. What is the volume of this iron ball in cubic centimeters?
Solution: The volume of a cube is 6*6*6=2 16 cubic centimeter, so the bottom area of a rectangular water tank is
216/1.2 =180 cm2
The volume of the iron ball is 180*0.9= 162 cubic centimeters.
Six, a bag of rice, eat two fifths, then eat 14kg, then * * * ate three quarters of this bag of rice, how heavy is this bag of rice?
Solution: set the original weight Xkg and get it according to the meaning of the question.
2/5X+ 14=3/4X
3/4X-2/5X= 14
7/20X= 14
X=40 (kg)
Seven, there are two piles of bricks, the first pile is 140, which exceeds 60% of the second pile. It is known that there are 1900 bricks in these two piles. How many bricks are there in the second pile?
Solution: Set the second pile of X blocks and set the equation.
X+60%X+ 140= 1900
1.6X = 1900- 140
X= 1 100 (block)
Eight, build a road, has been built 180 meters, 60 meters more than three quarters have not been repaired, how long is this road?
Solution: Let the path length be x meters and get the equation.
(X- 180)*3/4+60= 180
The solution is X=340 (m)