Question

Plz answer this question..............

Answer 1

given ,
height of tank = 98 cm
capacity of tank = 123.2 litres
capacity of tank means volume of tank
hence ,
volume of tank = 123.2 litres =123.2x 10^3 cm^3 = 123200 cm^3

volume of cylinder = pi. r ^2 .h
so,
pi .r ^2 . h = 123200
22/7 x r^2 x 98 = 123200
22 x 14 x r^2 = 123200
r^2 = 400
r = 20 cm
now ,
total surface area of 7 tanks = 7 x 2pi. r ( h + r)
= 14 x 22/7 x 20 x 118 cm^2
= 880 x 118 cm^2
now ,
cost = total surface area x rate
= 880 x 118 x 50/100
=88 x 118 x 5
=440 x 118
=51920 Rs

Answer 2

h=98 cm
Capacity= 123.2 litres
Vol. of tank= 123.2 × 1000 = 123200 cm3
Volume of cylinder= π×r×r×h
π×r×r×h = 123200
22/7×r×r×98= 123200
22×r×r×14= 123200
r×r= 400
r=√400 = 20 cm

TSA of 7 tanks = 7×2πr(h+r)
14×22/7×20×118 cm2
880×118 cm2
TSA × rate = 880×118×50/100
= 88×118×5
= 440×118
= 51920