The Meeting Point

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Another graph story for our Comenius project.

Transcript of The Meeting Point

  • THE MEETING POINT Because the spring comes with

    feelings of good cheer and warmth, four

    friends, Ana, Betty, Mara and Serena

    decided to go to the park, located near the

    school.

    Mara, more affected by the spring

    fatigue, hasnt been to school, but she

    thought it would be better to breathe some

    fresh air along with her friends. So, after

    she picked up some chocolate bars just in

    case and put them in her bag, she got out

    as soon as she received the text message from Betty and Serena, who had already gone out of the

    school yard. Mara walked slowly, knowing she is 300 m ahead, her block of flats being closer to

    the park than the school. After 3 minutes and a half, she had already walked 200 m and she was

    starting to feel anxious about the time of the meeting.

    Serena went from school directly towards the park, but due to her back problems, she

    decided to leave some

    books in a drawer in the

    classroom. In 4

    minutes, she reached

    the local shop, located

    400 m away from the

    school. In just 2

    minutes, she bought

    some juice, then she

    began running towards

    the meeting point when

    she came in a minute.

    Ana left from the

    school too, but with a

    delay of 3 minutes,

    because she stopped to

    borrow a book from the

    schools library.

    Because of this delay,

    she had to go faster to

    0

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    0 1 2 3 4 5 6 7 8

    Mara

    Serena

    Ana

    Betty

    t (min)

    CCCllliiinnn SSSiiimmmeeessscccuuu 888 CCC

  • recover lost time, so in just 2 minutes, she has walked 350 m, very quickly reaching the shop

    where Serena was waiting.

    Betty, the poet of the group, left school with Serena, but the magnificent trees and the

    beautiful scents have awakened her artistic sense, so she was hovering, gathering ideas, feelings

    and pictures, that she is going to use in her next poems for the school magazine and other

    literature contests. After 2 minutes, she was already 100 m away from the school and she didnt

    even notice Serena, when she had gone pass the store where she was staying. Betty kept walking

    until she reached 700 m in little over 7 minutes.

    At one point, the girls met, and the story of their journeys were transposed into a coordinate

    system by four graphs representing the distance each girl had traveled and their time, resolving the

    project for their mathematics lesson. The meeting point, where the graphs intersect, can be seen

    from the graph, but it can also be calculated.

    First, we determine the linear functions shown in the figure.

    We know that baxxf )( and ffGB

    GA)500;5,3(

    )300;0(

    .By solving the system of equations,

    5005,33000

    baba it results that 300b and

    7

    400a .

    So the straight blue line is the graph of the function 3007

    400)( xxf . In the same way we

    can calculate the other 2 functions.

    For the green chart, we have 525175)( xxf . P (x ; y) is the intersection point of the two

    graphs. From 5251753007

    400xx we can say that x=7 and y=700.

    Serena and Betty arrive in

    7 minutes at the meeting point,

    located 700 m from the school, so

    the four friends had met at the

    point P(7; 700) and a beautiful

    adventure began there, in a

    beautiful spring day in the park,

    near the school.

    Written in Romanian by

    Dimciu Mara, translated into English by Cisu Dragos VIII C.