📜  门| GATE-CS-2014-(Set-2)|第65章

📅  最后修改于: 2021-06-28 19:02:38             🧑  作者: Mango

时钟的分针和时针将在上午6点至上午7点之间的某个时间最接近60 o
(A)上午6:22
(B)上午6:27
(C)上午6:38
(D)上午6:45答案: (A)
解释:

Speed of the Hour hand = ( 360 degree ) / ( 12 * 60 minutes ) 
                       = 0.5 degree / minute.
Speed of the minute hand = ( 360 degree ) / ( 60 minutes ) 
                         = 6 degree / minute.

凌晨6点,时针将垂直向下指向时钟6,而分针将垂直向上指向时钟12。 (因此它们是相对的,它们之间有180度的间隙)。

现在,t分钟后,这两只手之间的夹角将是以下两只手之一:

(180 - 6t) + 0.5t, when the minute hand is 
                   behind the hour hand or,

6t - (180 + 0.5t), when the minute hand is 
                    ahead of hour hand,

Now the the question asks for angle of 60 degree.

Hence, 
(180 - 6t) + 0.5t = 60 , we get t = 21.8 minute
and
6t - ( 180 + 0.5t ) = 60, we get t = 48 minutess

因此,最接近答案的时间是22分钟,即上午6.22。因此答案是A。这个问题的测验