What is the total number of schools whose total SAT scores are greater or equal to 1500 whose mailing city is Lakeport?
Total SAT scores can be computed by AvgScrRead + AvgScrMath + AvgScrWrite
SELECT COUNT(T1.cds) FROM satscores AS T1 INNER JOIN schools AS T2 ON T1.cds = T2.CDSCode WHERE T2.MailCity = 'Lakeport' AND (T1.AvgScrRead + T1.AvgScrMath + T1.AvgScrWrite) >= 1500