Let |a| = 12 at an angle of 25° and |b| = 7 at an angle of 105°. What is the magnitude of a + b? Round to the nearest decimal. 12.8
14.9
15.4
17.3

1. according to the internal revenue service, the mean tax refund for the year 2007 was $2,708. assume the standard deviation is $650 and that the amounts refunded follow a normal probability distribution. a. what percent of the refunds are more than $3,000? b. what percent of the refunds are more than $3,000 but less than $4,000? c. what percent of the refunds are less than $2,000?