好望角234 2022-9-24 15:17
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top11 2022-9-25 17:23
[quote]原帖由 [i]好望角234[/i] 於 2022-9-24 15:17 發表 [url=https://www.discuss.com.hk/redirect.php?goto=findpost&pid=552338696&ptid=30782106][img]https://www.discuss.com.hk/images/common/back.gif[/img][/url]
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10 = 2 × 5
15 = 3 × 5
25 = 5²
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The L.C.M. of 10, 15, 25 is 2 × 3 × 5² = 150.
The side to place the brick with length 10 mm should have 150 ÷ 10 = 15 pieces.
The side to place the brick with length 15 mm should have 150 ÷ 15 = 10 pieces.
The side to place the brick with length 25 mm should have 150 ÷ 25 = 6 pieces.
Therefore, the least number of bricks needed is 15 × 10 × 6 = 900.