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想問幾條數學問題(英數)

想問幾條數學問題(英數)!!

麻煩今天5:00前回答!!

1.If there were 600 students in school last year, and 72 students left school in this year,find the percentage change in the number of students this year.

2.If there are 165 litres of water left in a water tank after using 45% of the tank's capacity during the day, find the capacity of the tank assuming that the tank was full in the morning.

3.There are four points P (-2,5) ,Q(-2,-3), R(-5,-6), S (4,-6) lying on a rectangular coordinate plane. If the point of intersection of line PQ and line RS is A,find the distance betweenAR.

4.What was the percentage change between 38.9 and 37.9?

5該!!

Update:

請快點答....

我明天數學考試喇....

請你們幫幫忙....

2 Answers

Rating
  • x39t44
    Lv 7
    1 decade ago
    Favorite Answer

    1.If there were 600 students in school last year, and 72 students left school in this year,

    find the percentage change in the number of students this year.

    (600-72)/600 *100% = 88% >>>>>>>>>>> so the no. of students decreases 12%.

    2.If there are 165 litres of water left in a water tank after using 45% of the tank's capacity during the day,

    find the capacity of the tank assuming that the tank was full in the morning.

    165 l /(1-45%) = 300 l >>>>>>>>>>>Therefore, the capacity of the tank ...in the morning is 300 litres.

    3.There are four points P (-2,5) ,Q(-2,-3), R(-5,-6), S (4,-6) lying on a rectangular coordinate plane.

    If the point of intersection of line PQ and line RS is A,find the distance betweenAR.

    oh...唔做得唔得?? 都搵唔到intersection point(I don't have that kind of paper)

    4.What was the percentage change between 38.9 and 37.9?

    From 38.9, it decreases 2.57% to 37.9 (cor. to 3sig. fig.)

    2009-06-11 16:32:25 補充:

    Sh!t, in the question no.4. I missed the step.

    (38.9-37.9)/38.9=2.57%(cor. to 3 sig. fig.)

    >>我都係聽日考數學添

    不過你第三條我就真係幫唔到你,係咪打錯左D野?

    Source(s): me
    • Commenter avatarLogin to reply the answers
  • 1 decade ago

    1.If there were 600 students in school last year, and 72 students left school in this year,find the percentage change in the number of students this year.

    The percentage decrease

    =72/600 x100%

    =12%

    2.If there are 165 litres of water left in a water tank after using 45% of the tank's capacity during the day, find the capacity of the tank assuming that the tank was full in the morning.

    The capacity of the tank

    =165/(1-45%)

    =300

    3.There are four points P (-2,5) ,Q(-2,-3), R(-5,-6), S (4,-6) lying on a rectangular coordinate plane. If the point of intersection of line PQ and line RS is A,find the distance betweenAR.

    they intersect ma???

    4.What was the percentage change between 38.9 and 37.9?

    The percentage change

    =(38.9-37.9)/38.9 x 100%

    =1000/389%

    Source(s): *以上純屬個人意見*
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