2. Apple 1000 kg, with water content of 96% at the time of storage; After one month, the water content was 95%. How many pounds have you lost in the overall weight of criticism?
Xiaohong and Xiaoming attended the party. Xiaohong saw twice as many students without glasses as those with glasses. Xiao Ming saw that students who wore glasses were two-thirds of those who didn't. How many students attended the party?
4.50 Students stand in a row facing the teacher and count from left to right according to the teacher's password: 123 ... After the report, the teacher asks the students who reported 4 times to turn back and the students who reported 6 times to turn back. Q: How many students are still facing the teacher?
Answer:
1.120/15% = 800 yuan.
(800-64)/80/(1+15%) = 8 yuan.
2. 1000 *( 1-96%)= 40k g。
40/( 1-95%)= 800 kg
1000-800=200 kg
3. 1/(2/2+ 1)-(3/3+2) = 15.
15+ 1= 16 (it's not easy to fight, so it's the only way)
4.50/4= 12 2
50/6=8 2
50/ 12=4 2
12+8-4= 16
50- 16=34
Since there is no time, let's ask these four questions.
Add a few more questions
1. It takes eight days for two people to do a project with the same work efficiency. When the task is half finished, A's efficiency will double, and B's efficiency will drop to 1/2. How many days will it take to complete this task?
2. You can draw a straight line at any two points on the crossing plane. There are eight points on the plane first. How many straight lines can you draw at least?
3. There are 17 classes in Grade Four, Grade Five and Grade Six, with 737 students. It is known that there are 15 students in each class of Grade Four, 43 students in Grade Five and 4 students in Grade Six. Q: How many classes are there in Grade 5 and 6?
4. The front wheel and rear wheel of bicycle can be interchanged. The tire can travel 5000 kilometers at the front wheel position and 3000 kilometers at the rear wheel position. Put on two new tires at the same time. How many kilometers is the most feasible?
5. For a section of highway, A has 10 days, B has 12 days, C has 15 days, D has 30 days, AB has two roads with the same length, and both parties are repairing at the same time. C started to help A fix it, and helped B fix it halfway. It is known that C walked for two days in the process of helping A, replaced by Ding, and the last two roads were repaired at the same time. How many days will it take to complete this task?
6. Two cars, A and B, start from AB at the same time and drive in opposite directions. It is known that the speed ratio of the two cars is 4: 3, C is between AB, and the time for the two cars to arrive at C is 8 am and 3 pm respectively. When did the two cars meet?
7. The circumference of a circle is 90 cm. Three points divide the circumference into three equal parts (as you imagine). Three kinds of reptiles are at these three points. They set out at the same time and crawled clockwise along the circle. A 10/0cm/sec, b5cm/sec, C3 cm/sec. The three reptiles returned to the same position for the first time in a few minutes after leaving.
8. There are three kinds of balls *** 160. If 1/3 of the red ball, 1/4 of the yellow ball and 1/5 of the white ball are removed, 120 remains. If you remove 1/5 for the red ball, 1/4 for the yellow ball, 1/3 for the white ball and 1 16. How much yellow autumn?
1. Suppose the efficiency is 1 and the workload is 8*2= 16 days.
8/(3+0.5)=2 and two-sevenths days 4+ 2 and two-sevenths days = 6 and two-sevenths days.
The meaning of this question is not clear. If you want to draw the least number of lines through all the points, then one line is enough, and all the points are on one line at this time.
3. Suppose they are all in the fourth grade.
45* 17=765 people
765-737=28 people
() *2+( )*4 (for calculation, make () *2 as much as possible)
= 15*2+ 1+4(2 and 4 are the differences between level 5 and level 4)
There are 13 classes.
This question is very difficult. Think of it this way. The tires of the front wheel and the tires of the rear wheel wear at the same time, and the wear ratio is 3: 5. In order to go further, the front and rear tires must be worn at the same time after changing the tires (only once). Therefore, it is assumed that the front wheel and the rear wheel wear 3x and 5x respectively before the exchange, and 1-5x and 1-3x respectively remain after the exchange. The ratio of the two is exactly 3: 5, and the equation is: (1-5x)/( 1-3x) = Therefore, during the exchange,
5. Column equation:110x+1/2x+115 (x-2)+1/30 * 2 = 2.
X=8 4/ 15
6. This question is ingenious. Suppose the speed of two cars is 4 times and 3 times per hour respectively. At 8 o'clock in the morning, A arrived at C, but B hasn't arrived yet. Suppose B is in D, and in the seven hours from 8: 00 to 3: 00 pm, B walks from D to C, that is to say, the CD distance is 7*3x=2 1x, and the problem becomes that from 8: 00 in the morning, two cars are driving in opposite directions, the distance is 2 1x, and the speeds are 4x and 3x respectively. So the answer is easy to get. 2 1x/(3x+4x)=3 hours, which means we meet at 8+3= 1 1 in the morning.
7. It is more difficult. The meaning of this question is unclear. "Same position" refers to the original position of the three worms or the three worms meet in the same place? If it is the former, the answer is the least common multiple of 90/ 10, 90/5, 90/3, which is 90 seconds. If it is the latter (assuming that ABC is arranged clockwise), assuming that it takes x seconds to complete, 10x-5x-30 and 5x-3x-30 are multiples of 90, that is, (5x-30)/90 and (2x-30)/90 are integers, and the smallest x is needed. X/30 obtained by subtracting two integers is an integer, and X is a multiple of 30. Through experiments, we know that the minimum x is x=60 seconds, that is, 1 minute.
(Similarly, if ABC is arranged counterclockwise, (5x-60)/90 and (2x-60)/90 are integers. The answer is 30 seconds or half a minute. )
8. List the equations. Let the number of three kinds of balls be x, y and z, then x+y+z= 160, x/3+y/4+z/5=40, and x/5+y/4+z/3=44. The third formula subtracts the second formula z-x=30, and the first formula and the second formula together eliminate Y to 5x=3z. X=45, z=75 can be obtained by combining these two formulas, and y=40 can be obtained by bringing them back to the first formula. There are 40 yellow balls.