Calculate the total water cost for the Ndlovu family, given their consumption and the municipality's water tariff structure.

The Ndlovu family used 27 kl of water.

• Block 1 (0 - 6 kl):

  • Volume used: $6 \text{ kl}$
  • Tariff: $\text{R}0.00/\text{kl}$
  • Cost: $6 \text{ kl} \times \text{R}0.00/\text{kl} = \text{R}0.00$

• Block 2 (6 - 10.5 kl):

  • Volume used: $10.5 \text{ kl} - 6 \text{ kl} = 4.5 \text{ kl}$
  • Tariff: $\text{R}17.37/\text{kl}$
  • Cost: $4.5 \text{ kl} \times \text{R}17.37/\text{kl} = \text{R}78.165$

• Block 3 (10.5 - 35 kl):

  • Remaining volume used: $27 \text{ kl} - 10.5 \text{ kl} = 16.5 \text{ kl}$
  • Tariff: $\text{R}23.87/\text{kl}$
  • Cost: $16.5 \text{ kl} \times \text{R}23.87/\text{kl} = \text{R}394.055$

$$\text{Total Cost} = \text{R}0.00 + \text{R}78.165 + \text{R}394.055$$ $$\text{Total Cost} = \text{R}472.22$$

The Ndlovu family will pay $\boxed{\text{R472.22}}$.