CTET 2 Social and Science Jan 2012 Paper

As India’s standard time has been taken, at 82°30’ from the Naini village of Allahabad. So the difference between Ahmedabad and Indian Standard Time$={82}^{\circ }{30}^{\mathit{I}}-{72}^{\circ }{30}^{\mathit{I}}$
$=10°$
∴Difference in Time on 1° longitude = 4 minutes
∴Time 10° longitude = 40 minutes
∴Ahmedabad is situated on the East of Allahabad.
∴Time of Ahmedabad will be $=08:00\mathit{–}00:40$
$=7:20\mathit{a}\mathit{m}$