What time is it at 90 west longitude if is is 3 pm at 45 west?

At 90 degrees west longitude, the time will be one hour earlier than at 45 degrees west longitude. Since there are 15 degrees of longitude for each hour of time difference, moving from 45 west to 90 west (a difference of 45 degrees) equates to a time difference of three hours. Therefore, if it is 3 PM at 45 west, it would be 12 PM (noon) at 90 west longitude.