Given,
Height of tank = 6 × radius of tank
Let radius of tank = r decimeter
So, height of tank = 6r dm
Total surface area of tank = \(\cfrac{198\times100}{50}\) dm2
= 2πr(h + r) = 198 × 2
= 2πr(7r) = 396
= r2 = \(\cfrac{396\times7}{14\times22}\) = 9
r = 3 dm
Height = 6r = 6 × 3 = 18 dm
So, volume of tank = πr2h = \(\cfrac{22}7\times\)9\(\times\)18 = 509.14 dm3