Answer:
7
Step-by-step explanation:

This is the sum of the first three terms of a geometric sequence, where the first term is 4 and the common ratio is ½.
We can use a formula to find the sum, or, since there's only three terms, we can find the value of each term then add up the results.
4 · (½)¹⁻¹ = 4
4 · (½)²⁻¹ = 2
4 · (½)³⁻¹ = 1
4 + 2 + 1 = 7
216/18 is 12 so you would multiply 3 and 12 to get 36 grams of tea leaves