F.2 Inequalities

2008-01-08 10:11 pm

次次都計到7...但係答案係6...點計呀= =
Tim played a game with Jack for severl rounds. The winner of each round scored 4 marks while the loser lost 1 mark. They played the game for 15 rounds and there was no tie games. If the score of Tim was less than 30 marks, find the least number of rounds that Jack won.

回答 (1)

¦ý´²

2008-01-09 12:13 am

✔ 最佳答案

For 15 rounds of games they played,
If Tim win 7 games, the marks he will get
= 7x4+(15-7)x(-1)
= 28-8
=20
If Tim win 8 games, the marks he will get
= 8x4+(15-8)x(-1)
= 32-7
=25
If Tim win 9 games, the marks he will get
= 9x4+(15-9)x(-1)
= 36-6
=30
If the score of Tim was less than 30 marks, max. no. of rounds that Tim can won is 8. Therefore,
the least number of rounds that Jack won
= 15-8
=7 nos. of rounds
If the question becomes ".... If the score of Tim was less than or equal to 30 marks ....", the least number of rounds that Jack won = 15-9 =6 nos. of rounds.

參考: my math. knowledge

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