用x,y.....唔該哂......
7.There are 37 blue marbles ,red marbles and yellow marbles in a box .If the number of red marbles is twice that of the blue ones ,and the number of yellow marbles is 5 more than that of the blue ones, how many marbles of each kind are there?
f.2 Simultaneous Linear Equations in Two Unknowns(4)
2007-02-25 5:29 am
回答 (1)
2007-02-25 5:40 am
✔ 最佳答案
yellow marbles=blue marbles+5Let x be the no. of red marbles and y be the no. of blue marbles.
x+y+y+5=37......(1)
x=2y......(2)
sub. (2) into (1):
x+y+y+5=37
2y+y+y+5=37
4y=32
y=8
sub. y=8 into (2):
x=2y
x=2(8)
x=16
the no. of yellow marbles
=8+5
=13
There are 16 red marbles, 8 blue marbles and 13 yellow marbles.
參考: myself
收錄日期: 2021-04-12 21:24:40
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