2019 Junior Kangaroo-教师用卷
- zhou
-
0 次阅读
-
0 次下载
-
2022-12-26 21:08:35
微信
赏
支付宝
文档简介:
2019JuniorKangaroo-教师用卷教师用卷1、【来源】(2019JuniorKangarooQuestion#1)Rianahasbeenaskedtoerasedigitsfromthenumber12323314toobtainanumberwhichreadsthesamefromlefttorightasitdoesfromrighttoleft.WhatisthesmallestnumberofdigitsRiananeedstoerase?()A.1B.2C.3D.4E.5【答案】C;【解析】Theonlydigit4isattheendofthenumberandhencetoobtainanumberwhichreadsthesamefromlefttorightasitdoesfromrighttoleft(knownasapalindromicnumber),thefirststepistoerasethe4leavingthenumber1232331.Therearenowthreedifferentpossibilitiestoproduceapalindromicnumber-erasingthetwo2toleave13331,erasingthefinaltwo3toobtain12321orerasingthefirst2andtheeitherthelastorsecondlast3toobtain13231.However,ineachcasethreedigitshavebeenerased.2、【来源】(2019JuniorKangarooQuestion#2)Thediagramshowssquaresofthreedifferentsizesarrangedintoarectangle.Thelengthofeachsideofthesmallestsquaresis20cm.AdamAntwalksalongthepathmarkedfromto.HowfardoesAdamwalk?()
评论
发表评论