The formula<span> will be a</span>n<span> = a</span>12n - 1<span> or a</span>n<span> = (1)2</span>n - <span>1</span>
Ok. So since they give you that 1/2 cup of soup equals 120 milliliters it makes this very easy. So since we know 120milliliters=1/2 and that 3 1/2= 7 1/2s (please note that the 7 1/2s doesnt mean seven and 1/2 it means seven 1/2s) you just add 120 to itself 7 times getting an answer of 840. (please vote brainliest ^^)