Answer: 15
Step-by-step explanation:
By the trapezoid midsegment theorem,

-1/5of 15 =-3 then add 3 2/5th which is 17/2 so -3+17/2 = 11/2=5 1/2
So firstly, multiply both sides by t: 
Next, add both sides by v0, and your answer will be: 
.h.i. i think i know the answer