算式 or 中文解釋
5. In Patrick Ho Memorial School , there are 5 Form 1 class. If there are 3a boys and 2d girls in each class , find the number of Form 1 students in the school.
6, There are two brands of pen A and B available in the bookstore . The prices of brand A and B pens are $6 and $8 respectively . If Peter wishes to spend just $82 to buy 12 pens , how many pens of each brand should he buy?
F. 1 Maths.....(easy)
2007-03-31 10:14 pm
回答 (3)
2007-03-31 10:20 pm
✔ 最佳答案
5. number of Form 1 students = 5(3a+2d) = 15a+10d每班有3a+2d人, 有5班, 所以有5*(3a+2d)人
6.Let a be the number of pen A
and b be the number of pen B
6a+8b=82----(1)
a+b=12----(2)
2 equations and 2 unknowns
(1)-6*(2): 2b=10 --> b=5
sub b=5 into either equation, get a=7
2007-03-31 14:26:16 補充：
you should try first
參考: 自己
2007-04-01 1:18 am
5)There are 5 Form1 class
There are 3a boys and 2d girls in each class
Therefore, the number of Form 1 students in the school=5x( 3a+2d )
6)Let a be the number of pens of brand A
and b be the number of pens of brand B
a+b=12---------(1)
6a+8b=$82 ---(2)
from (1) a=12-b-----(3)
sub (3) into (2)
6(12-b)+8b=82
72-6b+8b=82
2b=10
b=5-------(4)
sub (4) into (3)
a=12-5
a=7
He should buy 7 pens of brand A and 5 pens of brend B
There are 3a boys and 2d girls in each class
Therefore, the number of Form 1 students in the school=5x( 3a+2d )
6)Let a be the number of pens of brand A
and b be the number of pens of brand B
a+b=12---------(1)
6a+8b=$82 ---(2)
from (1) a=12-b-----(3)
sub (3) into (2)
6(12-b)+8b=82
72-6b+8b=82
2b=10
b=5-------(4)
sub (4) into (3)
a=12-5
a=7
He should buy 7 pens of brand A and 5 pens of brend B
2007-03-31 10:22 pm
5. 5 X (3a +2d)
= 15a +10d
6. Let the number of brand A pens he should buy be x, brand B be (12-x).
6x + 8(12-x) = 82
...... (do this yourself)
= 15a +10d
6. Let the number of brand A pens he should buy be x, brand B be (12-x).
6x + 8(12-x) = 82
...... (do this yourself)
參考: me
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