a+b/c=11 b+a/c=14 求（a+b)/c 过程

设A = PC
B = QC
原两式相加：
A + B + A/C + B/C
= (A + B) + (A + B)/C
= (A + B)(1 + C)/C
= (P + Q)(1 + C)
= 11 + 14 = 25
P + Q ≥ 2
1 + C ≥ 2
且25 = 5 × 5，知：
P + Q = 5
1 + C = 5，C = 4