Three vessels have the same base area, 0.020 m², and hold water to the same depth, 0.30 m…

Step 1. Pressure. $1000\ \text{kg/m}^3 \times 9.8\ \text{m/s}^2 \times 0.30\ \text{m} = 2940\ \text{Pa}$, the same in all three.

Step 2. Force. $2940\ \text{Pa} \times 0.020\ \text{m}^2 = 58.8\ \text{N}$ on each base.

Step 3. Why. In the wide vessel the sloping walls hold up the extra water; in the narrow one the walls push down on the water.