Question

（满分12分）为了防控甲型H1N1流感，某校积极进行校园环境消毒，购买了甲、乙两种消毒液共100瓶，其中甲种6元/瓶，乙种9元/瓶．

1.（1）如果购买这两种消毒液共用780元，求甲、乙两种消毒液各购买多少瓶？

2.（2）该校准备再次购买这两种消毒液（不包括已购买的100瓶），使乙种瓶数是甲种瓶数的2倍，且所需费用不多于1200元（不包括780元），求甲种消毒液最多能再购买多少瓶？

 

Answer 1

 

1.（1）解法一：设甲种消毒液购买瓶，则乙种消毒液购买瓶．··················· 1分

依题意，得．

解得：．············································································································ 3分

（瓶）．················································································ 4分

答：甲种消毒液购买40瓶，乙种消毒液购买60瓶．····················································· 5分

解法二：设甲种消毒液购买瓶，乙种消毒液购买瓶．·············································· 1分

依题意，得·························································································· 3分

解得：············································································································· 4分

答：甲种消毒液购买40瓶，乙种消毒液购买60瓶．

2.（2）设再次购买甲种消毒液瓶，刚购买乙种消毒液瓶．··································· 6分

依题意，得．················································································· 8分

解得：．··········································································································· 9分

答：甲种消毒液最多再购买50瓶．

解析:略