Answer: p = 32
Explanation:
Assuming that QV is parallel to ST, we can use the midsegment theorem, which basically means that (QV + ST)/2 is RU.
From here you get the equation (3p - 49 + p + 39)/2 = p + 27
Then multiply both sides by 2, and combine like terms to get:
4p - 10 = 2p + 54
Further simplify:
2p = 64
p = 32.