Need your on this im still stuck

the total cost of an item including sales tax is directly proportional to its price. if the total cost of a $24 item is $25.44, what is the total cost on a $75 item?

my possibile answers:

a. $79.50

b. $106

c. $76.44

d. $795

Idon’t understand this.. will someone ? will mark brainliest along with 20 points.

Lorne subtracted 6x3 – 2x + 3 from –3x3 + 5x2 + 4x – 7. use the drop-down menus to identify the steps lorne used to find the difference.

Marco is studying a type of mold that grows at a fast rate. he created the function f(x) = 345(1.30)x to model the number of mold spores per week. what does the 1.30 represent? how many mold spores are there after 4 weeks? round your answer to the nearest whole number. 1.30 represents the number of mold spores marco had at the beginning of the study; 985 mold spores 1.30 represents the number of mold spores grown in a given week; 448 mold spores 1.30 represents the 30% rate of weekly growth; 345 mold spores 1.30 represents the 30% rate of weekly growth; 985 mold spores