Elitmus
Exam
Numerical Ability
Clocks and Calendars
If there r 36 hrs in a day. n 18 hrs displayed on a clock. n 90 min in 1 hr n 60 sec in 1 min. If time is 15:50 AM. what is the angle b/w the two needle.
Read Solution (Total 13)
-
- hours hand will sweep 360/18=20 degree each hours
minute hand will sweep 360/90=40 degree each minute
for 15 hours angle sweep for hour hand will be 15*20=300 degree
now 1 hour = 90 minute => 50 minute=50/90 hours
thus hour hand will move (5/9)*20=11.11 degree
so total angle sweep by hour hand will be 300+11.11=311.11
now minute hand will sweep 50*40=200 degree
so the angle between the two hand will be 311.11-200=111.11 degree
or 360-111.11=248.89 degree - 10 years agoHelpfull: Yes(17) No(2)
- the clock is circular and hence a complete rotation of hand (hour, minute or second) will sweep a 360 degrees for full rotation. Since there are 18 hrs that can be displayed each hour will have a sweep angle of 360/18 = 20 degrees. Similarly minutes will have 360/90 = 4 degrees.
Now, we have, 15*20 = 300 degrees for hour hand
and 50*4 = 200 degrees for minute hand
Therefore angle between two needle is: 300-200 = 100 degrees.
However, considering a practical analog clock the answer would be less than 100 degrees as hour hand traverses little with the minute hand. - 10 years agoHelpfull: Yes(11) No(7)
- In 15 hour 50 mint hour hand will complete 15*20+(20*50)/90=311 degree (apex)
Mint hand 50*4=200
Difference =111 degree - 10 years agoHelpfull: Yes(7) No(1)
- For hour hand:
It covers 360deg. In 18 hrs . Hence hrs hand covers 20deg per hour or hand hour covers 2/9deg per minutes (1hr=90 minute)
For minute hand :
it covers 360deg in 90 minutes. Hence it covers 4deg per min.
so,
In 50 minutes, minute hand covers 50*4=200deg
In 15 hrs, hour hand covers 15*20=300deg and in 50 min, it also covers 50*2/9=100/9 deg
so, angle between minutes hand and hours hand=
300+100/9 - 200 =111.11(appox.).
This is correct way
- 10 years agoHelpfull: Yes(7) No(0)
- 15:50 am = 15 hours out of 18 and 50 minutes out of 90
hour angle = (15/18)*360 degrees = 300 degrees
minute angle = (50/90)*360 degrees = 200 degrees
angle b/w minute hand and hour hand = 300 - 200 degrees = 100 degrees - 10 years agoHelpfull: Yes(2) No(3)
- Pankaj there must be a displacement in hour hand for 50 mint of time
- 10 years agoHelpfull: Yes(1) No(2)
- 111.11 degree
- 10 years agoHelpfull: Yes(1) No(0)
- 117 degrees...because it would be same as 24 hr and 12hr..because the ratio remained unchanged..
- 10 years agoHelpfull: Yes(0) No(2)
- 100 degrees..
- 10 years agoHelpfull: Yes(0) No(2)
- ak can u please explain how???
- 10 years agoHelpfull: Yes(0) No(1)
- In 15 hour 50 mint hour hand will complete->(15+(20*50))/90=311 degree (apex)
Mint hand 50*4=200
Difference =111 degree - 10 years agoHelpfull: Yes(0) No(0)
- answer would be 1000/9
- 9 years agoHelpfull: Yes(0) No(0)
- use shortcut
if its as usual clock use the formula 30(h+m/60)-6m
for this qoestion
use 20(h+m/90)-4m
u could get 111.1 deg - 9 years agoHelpfull: Yes(0) No(0)
Elitmus Other Question