(PLEASE HELP ME PLEASE PLEASE PLEASE) the sum of spongebob squidward and plankton's ages is 174. Squidward is 4 more than twice the age of plankton. Spongebob is 2 years less than planktons age. Find out all their ages

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?