The area of the base of a rectangular tank is 6500 cm2 and the volume of water contained in it is 2.6 m3.

(b) 4 m

Area of the base of a rectangular tank $=6500 \mathrm{~cm}^{2}$

$=\left(\frac{6500}{100 \times 100}\right) \mathrm{m}^{2}$

$=\frac{13}{20} \mathrm{~m}^{2}$

Let the depth of the water be d metres.
Then,

$\frac{13}{20} \times d=2.6$

$\Rightarrow d=\left(\frac{26}{10} \times \frac{20}{13}\right) \mathrm{m}$

$\Rightarrow d=4 \mathrm{~m}$