"Application of linear equations in two variables" PPT courseware

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"Application of linear equations in two variables" PPT courseware

Part One: Itinerary Issues

basic quantitative relationship

distance = time x speed

time=distance/speed

speed=distance/time

Traveling in the same direction at the same time, distance = sum of time x speed

Traveling in the same direction at the same time, distance = time × speed difference

The speed of the boat in smooth water = the speed of the boat in still water + the speed of the current

The speed of the boat in upstream water = the speed of the boat in still water - the speed of the current

PPT on the application of linear equations of two variables, part 2: analysis of examples

Example 1. There are two cars A and B at a certain station. If car A sets off first and then car B sets off 1 hour later, car B will catch up with car A 5 hours after starting. If car A goes 30km first and then car B sets off, then car B will catch up with car A. 4 hours after departure, the distance traveled by vehicle B is 10km longer than the distance traveled by vehicle A. Find the speed of the two cars.

Example 2. An express train is 230 meters long and a slow train is 220 meters long. If the two trains are traveling in the same direction, it will take 90 seconds from when the express train catches up with the slow train to when it leaves the slow train. It only takes 18 seconds to leave the local train when they meet. What are the speeds of the express train and the local train?

Example 3. Two people A and B are practicing running on a circular track with a circumference of 400m. If they start in opposite directions, they will meet every 2.5 minutes; if they start in the same direction, they will meet every 10 minutes. It is assumed that the speed of the two people does not change, and A is faster than B Slow, find the speed of A and B.

Example 4. It is known that the distance between the two piers A and B is 240km. A bow ship sails between the two piers A and B. It takes 4 hours to sail with the current and 6 hours to sail against the current. Find the distance of the ship in still water. speed and velocity of water flow.

PPT on the application of linear equations in two variables, part three: engineering problems

Workload = working time × work efficiency

Working hours = workload/work efficiency

Work efficiency = workload/working time,

Example 1. A worker originally planned to process a batch of parts within a limited time. If 10 parts are processed per hour, it can be completed by 3 parts; if 11 parts are processed per hour, it can be completed 1 hour ahead of schedule. How many parts are there in this batch? How many hours will it take to complete according to the original plan?

Solution: Suppose there are x parts in this batch and it will take y hours to complete according to the original plan. According to the meaning of the question, we get

10y=x+3

11(y-1)=x

solution

X=77

Y=8

Answer: There are 77 parts in this batch, and it will take 8 hours to complete as planned.

PPT on the application of linear equations in two variables, part 4: commodity economic issues

Sum of principal and interest = principal + interest

Interest = principal × annual interest rate × number of periods × interest tax

Interest income tax = interest amount × 20�

Example 1 Li Ming saved 2,000 yuan and 1,000 yuan in two forms respectively. After one year, he took them all out. After deducting the interest and income tax, he could get an interest of 43.92 yuan. It is known that the sum of the annual interest rates of these two savings is 3.24. Question: What is the annual interest rate for each type of savings? (Note: Interest income tax payable by citizens = interest amount × 20�)

Solution: Assume that the annual interest rates of these two savings are x and y respectively. According to the question, we get

x+y=3. 24%

2000x80%+1000y80%=43.92

solution

x=2.25%

y=0.99%

Answer: The annual interest rates for these two types of savings are 2.25% and 0.09% respectively.

Keywords: Free download of Hebei Education Edition mathematics PPT courseware for seventh grade volume 2, PPT download of application of linear equations in two variables, .PPT format;

For more information about the PPT courseware "Applications of Systems of Linear Equations of Two Variables", please click on the "Applications of Systems of Linear Equations of Two Variables" ppt tag.

"Applications of Systems of Quadratic Equations" PPT:

"Applications of Linear Equations of Two Variables" PPT Part One: Review the past and learn the new. List the basic steps for solving word problems with linear equations of one variable. What is the key to solving word problems using equations? Find the equivalence relationship. The problem of two horses carrying a load is a widely circulated question in ancient India..

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Update Time: 2024-09-30

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