Use the geometric series formula to find the 9th term in this progression : 12 18 27...

Formula for nth term in a geometric progression = ar^n-1

workings:  

a=12

r=1.5  because 18/12 = 1.5

Thus, using ar^n-1  -->   12 * 1.5^8 = 307.54... or 308 (to 3sf)

(In an ideal scenario question we'd be working with a whole number as the answer, but i created this question in about a minute so couldn't ensure the answer would be a whole number).