Help balance please!!! H2O + As + HClO3 ----> H3AsO3 + HClO?

Let the balanced equation :
a H₂O + b As + c HClO₃ → d H₃AsO₃ + e HClO
where a, b, c, d and e are coefficients.

No. of H : 2a + c = 3d + e ...... [1]
No. of O : a + 3c = 3d + e ...... [2]
No. of As : b = d ...... [3]
No. of Cl : c = e ...... [4]

[1] - [2] :
a - 2c = 0
a = 2c

From [4] :
e = c

Put a = 2c and e = c into [1] :
2(2c) + c = 3d + c
3d = 4c
d = (4/3)c

Put d = (4/3)c into [3] :
b = (4/3)c

Then, a : b : c : d : e
= 2c : (4/3)c : c : (4/3)c : c
= 2 : (4/3) : 1 : (4/3) : 1
= 2×3 : (4/3)×3 : 1×3 : (4/3)×3 : 1×3
= 6 : 4 : 3 : 4 : 3

The balanced equation is :
6 H₂O + 4 As + 3 HClO₃ → 4 H₃AsO₃ + 3 HClO

6 H2O + 4 As + 3 HClO3 = 4 H3AsO3 + 3 HClO