Jose had 200 buckets, and each bucket had a mass of 20 kg. The mass decreased in the ratio 29:32. What was the total mass lost?

Jose had 200 buckets, and each bucket had a mass of 20 kg.

$$\text{Total initial mass} = 200 \text{ buckets} \times 20 \text{ kg/bucket} = 4000 \text{ kg}$$

The mass decreased in the ratio 29:32. This means that the new mass is $\frac{29}{32}$ of the original mass.
The fraction of mass lost is the difference between the original fraction (1) and the remaining fraction:

$$\text{Fraction lost} = 1 - \frac{29}{32} = \frac{32}{32} - \frac{29}{32} = \frac{3}{32}$$

Multiply the total initial mass by the fraction of mass lost.

$$\text{Total mass lost} = 4000 \text{ kg} \times \frac{3}{32}$$ $$\text{Total mass lost} = \frac{12000}{32} \text{ kg}$$ $$\text{Total mass lost} = 375 \text{ kg}$$

The final answer is $\text{375 kg}$.