Iam super confused on how to answer this, none of the answers work but i need a second pair of eyes.

Which statement shows that 6.24 is a rational number? a. 6.24 = 6.242424 b. 6.24 = 6.24 c. 6.24 = 68⁄33 d. 6.24 = 66⁄25

1. if events a and b are non-overlapping events, how do you find the probability that one or the other occurs? 2. what does it mean if p(a or b) equals 1?

The floor of a building consists of 3000 tiles which are rhombus shaped and each of it's diagonals are 45 cm and 30 cm in length. find the total cost of polishing the floor, if the cost per m² is rs. 4.