Answer:
15. 9 and 54; 16. 14 and 50; 17. 7 and 62;18. 3 and 50
Explanation:
If QR bisects ∠PQS, ∠PQR = ∠RQS
15.
∠PQR = ∠RQS

∠PQS = 2∠PQR = 2 × 27 = 54
16.
∠PQS = 2∠PQR

∠PQS = 4×14 - 6 = 56 - 6 = 50
17 .
∠PQR = ∠SQR

∠PQR = 5×7 - 4 = 35 - 4 = 31
∠PQS = 2∠PQR = 2 × 31 = 62
18.
∠PQR = ∠SQR

∠PQR = 8×3 + 1 = 24 + 1 = 25
∠PQS = 2∠PQR = 2 × 25 = 50