首页
登录
职称英语
When a certain stretch of highway was rebuilt and straightened,the distance alon
When a certain stretch of highway was rebuilt and straightened,the distance alon
游客
2024-01-13
44
管理
问题
When a certain stretch of highway was rebuilt and straightened,the distance along the stretch was decreased by 20 percent and the speed limit was increased by 25 percent.By what percent was the driving time along this stretch reduced for a person who always drives at the speed limit?
选项
A、
B、
C、
D、
E、
答案
B
解析
Let D and r be the distance and speed limit, respectively, along the stretch of highway before it was rebuilt. Then, the distance and speed limit along the stretch of highway after it was rebuilt are given by 0.8D and 1.25r. It follows that the percent reduction in time is
Alternatively, it helps to use actual numbers when calculating percent change, with 100 being the most mathematically convenient number to use. For this problem, set the speed limit at 100 miles per hour and the distance at 100 miles.
A 20 percent decrease in distance makes the new distance 80 miles. A 25 percent increase in speed limit makes the new speed limit 125 miles per hour, which, of course, is unrealistic, but very convenient to work with. Then, the new time distance/rate is 80/125 hours, The percent change in time is
The correct answer is B.
转载请注明原文地址:https://tihaiku.com/zcyy/3360093.html
相关试题推荐
Ofcourseacertainamountofdependenceonothersisnotonlygood,butneces
WINK,Inc.followsacertainprocedurethatrequirestwotaskstobefinishedin
Closingpricesforacertainstockwererecordedeachdayforaweekinthetabl
Acertaintirecompanycanproducetiresatacostof$22,500perbatchplus$9
Atypeofextra-largeSUVaverages12.2milespergallon(mpg)onthehighway,b
Acertainprosthodontistspecializesinimplantinggoldandsilverteethinhis
Inacertainconservativemutualfund,70percentofthemoneyisinvestedinbo
Inacertaingrowthfund,3/5oftheinvestmentcapitalisinvestedinstocks,a
Acertaintruckuses18gallonsofdieselfuelintraveling270miles.Inorder
Inacertainflowershop,whichstocksfourtypesofflowers,thereare-asman
随机试题
ThecultureoftheUnitedStatesisaWesterncultureoriginallyinfluence
[originaltext]W:Hello,Iboughtthislaptopcomputeralittleoveramonthago
WhenDidAidsBegin?Theyea
【B1】[br]【B8】[originaltext]Acaninecoptookearlyretirementafterbossesat
消防水泵按用途可分为供水消防泵、稳压消防泵、供泡沫液消防泵。
共用题干 MenTooMaySufferFromDomesticV
有一64岁女性患者,近2年来发现外阴左侧有一肿块,疼痛,2个月前破溃,且有血性分
根据下列资料,回答下列问题。 据报道,2013年3月英国政府宣布,从10月份起
个别指导法的优点包括()。A:可以避免新员工的盲目摸索 B:有利于企业传统
火灾报警系统由( )合成,是保障隧道安全运行系统中的一个重要子系统。A.人工手动
最新回复
(
0
)