A:lost $20
B:gained $10
C:gained $60
D.had no gain and loss
which in correct and why?
更新1:
Dion: 點解係divide??
更新2:
咩係名數??
maths
2012-05-14 8:46 am
Mary sold two bags for $240 each.She gained 20% on one and lost 20% on the other.After the two transaction.Mary
A:lost $20
B:gained $10
C:gained $60
D.had no gain and loss
which in correct and why?
A:lost $20
B:gained $10
C:gained $60
D.had no gain and loss
which in correct and why?
回答 (3)
2012-05-20 1:30 am
(selling price- cost price)/cost pricex100%=20%
(240-c)/c=1/5
240-c=c/5
240=c/5+c
240x5=5(c/5+c)
1200=c+5c
1200=6c
c=200
(E個系EARN的)
(cost price- selling price)/cost pricex100%=20%
(c-240)/c=1/5
c-240=c/5
-240=c/5-c
5(-240)=5(c/5-c)
-1200=c-5c
-1200=-4c
c=300
(E個系LOST)
300+200=500(totally cost)
240*2=480(selling price)
500-480=20
so, he lost $20
the correct answer isA
(240-c)/c=1/5
240-c=c/5
240=c/5+c
240x5=5(c/5+c)
1200=c+5c
1200=6c
c=200
(E個系EARN的)
(cost price- selling price)/cost pricex100%=20%
(c-240)/c=1/5
c-240=c/5
-240=c/5-c
5(-240)=5(c/5-c)
-1200=c-5c
-1200=-4c
c=300
(E個系LOST)
300+200=500(totally cost)
240*2=480(selling price)
500-480=20
so, he lost $20
the correct answer isA
參考: me
2012-05-14 8:41 pm
要還原番就要divide,名數除名數等於不名數
2012-05-14 9:13 am
A: lost $20
1st bag (gained 20%):
sold for $240
cost = 240 / (1+20%) = $200
gained $40
2nd bag (lost 20%):
sold for $240
cost = 240 / (1-20%) = $300
lost $60
40-60= -20
Mary lost $20
1st bag (gained 20%):
sold for $240
cost = 240 / (1+20%) = $200
gained $40
2nd bag (lost 20%):
sold for $240
cost = 240 / (1-20%) = $300
lost $60
40-60= -20
Mary lost $20
收錄日期: 2021-04-29 22:45:07
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