(1)兄弟象已賽完上半球季賽程的3/5,戰績為21勝9敗,如果想將上半球季提升至75%以上 則未來的賽程中,最多只能輸幾場?
A:已賽完的3/5,21+9=30 未賽的2/5,30除3/5 - 30=20
x/50=75% ,x=37.5(比賽沒有0.5,所以是38場)
至少要贏38-21=17場 ,最多可輸20-17=3
(2)數線上由左而右A、B、C三點,AB線段=18, BC=11,已知A、B、C分別以每分鐘8、6、5.5速率向右移動,且在X分鐘後,三點位置由左而右依 序為B A C ,求下 列何數可能是X值?
A:A每分鐘接近B ,8-6=2
AB線段=18 ,18/2=9 (A要超越B要+1所以是10分鐘)
X=10
(3)若10、A+5、2A+8為三角形三邊長,則A的範圍?
A:依三角形邊角關係:三角形的任兩邊和必大於第三邊
10+A+5>2A+8 , A<7
10+2A+8>A+5 , A>-13
3A>-3 , A<-1
A的範圍:7>A>-13
{第三題我不太確定喔!!}
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