Please answer this correctly

What is the simplified form of (3.25x10^3)(7.8x10^6) written in scientific notation?

60 musicians applied for a job at a music school. 14 of the musicians play both guitar and drums, 28 play drums, 18 play the guitar. what is the probability that the applicant who gets the job plays drums or guitar?

Arectangular garden is 5 feet long and 3 feet wide. a second rectangular garden has dimensions that are double the dimensions of the first garden. what is the percent of change in perimeter from the first garden to the second garden?