If the standard meridian is 82°30' E and the standard time at longitude 90°E is known to be 8 hr 30 m, the corresponding local mean time at the place will be

ANS:D - 9 hr 00 m

Difference between standard meridian and the longitude of the given place = 90' E - 82'30'' E =7' 30''

Local Mean time = ?

Every 1o E longitude increase in the 4 minutes time also increased

standard meridian is 82'30'' E = 8 hrs 30 min
90' - 82'30'' = 7'30''
7'30''x 4 mins = 30 mins 0 seconds.
Local mean time = Standard time+30 minutes 0 seconds,
= 8 hrs 30 min + 30 min 0 seconds.
= 9hrs, 0 minutes and 0 seconds.