中一升中二数学题

(1) 20x(1+r%)=26
1+r% =26/20
1+r% =1.3
r% = 3
r = 30

(2) 30x(1-r%)=28.2
1-r% =28.2/30
-r% = -0.06
r% = 0.06
r = 6

(3) mx(1+10%)=77
m(110%) =77
m(1.1) =77
m = 77/1.1
m = 70

(4) nx(1-10%)=90
n(90%) = 90
n(0.9) = 90
n = 90/0.9
n = 100

最佳解答

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回答者： sukie_090926 ( 小學級 3 級 )
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回答時間： 2007-08-08 10:05:42
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(1) 20x(1+r%)=26

1+r% =26/20

1+r% =1.3---------?

r% = 3------------?

r = 30
(1)20x(1+r%)=26

1+r%=26/20

1+r%=1.3

r%=0.3

r=30
应该是这样吧：
(1)20x(1+r%)=26

1+r%=26/20

1+r%=1.3

r%=0.3

r=30

(1)20x(1+r%)=26
1+r%=26/20
1+r%=1.3
r%=0.3
r=30

(2)30x(1-r%)=28
1-r%=28/30
1-r%=14/15
-r%= -1/15
r = -320/3

(3)mx(1+10%)=77
m=77/(1+10%)
m=70

(4)nx(1-10%)=90
n=90/(1-10%)
n=81

(1) 20x(1+r%)=26
1+r% =26/20
1+r% =1.3
r% = 3
r = 30

(2) 30x(1-r%)=28.2
1-r% =28.2/30
-r% = -0.06
r% = 0.06
r = 6

(3) mx(1+10%)=77
m(110%) =77
m(1.1) =77
m = 77/1.1
m = 70

(4) nx(1-10%)=90
n(90%) = 90
n(0.9) = 90
n = 90/0.9
n = 100