( Extra Credit ) Blog Reader iPhone App : Instead of dates display the age of a blog post.

I'm trying to complete this extra credit and I've managed to print in the console the Age of the post. I try to return secondsBetween back but there is an error "'NSTimeInterval' (aka 'double') to parameter of incompatible type 'NSDate *'"

Does anyone provide guidance on how i can fix my code? I think because i'm trying to return a NSTimeInterval which is causing the problem but I'm still trying to learn and get comfortable calling methods from classes.

-(NSString *) formatDate{ NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];

NSDate *tempDate = [dateFormatter dateFromString:self.date];

NSDate *today = [NSDate date];
NSTimeInterval secondsBetween = [today timeIntervalSinceDate:tempDate];

int numberOfDays = secondsBetween / 86400;
NSLog(@"# of days: %d", numberOfDays);

[dateFormatter setDateFormat:@"MMM-dd-yyyy"];
return [dateFormatter stringFromDate:secondsBetween];

}