Question
The radii of two solid right circular cylinders are 11
cm and 9 cm respectively and their heights are (h+1) cm and (2h+1) cm respectively. If the areas of the whole surface of the two cylinders are equal, then the ratio of their volumes is:Solution
Whole surface area of cylinder = 2Ï€R(H+R) 2Ï€ x 11[h+1+11] = 2Ï€ x 9[2h+1+9] 11[h+12] = 9[2h+10] 11h+132 = 18h+90 7h = 42 h = 6 so, V1/V2 = (Ï€ x 112 x (h+1))/(Ï€ x 92 x (2h+1)) Â Â Â Â Â = (121 x (6+1))/(81 x (2 x 6+1)) Â Â Â Â Â = (121 x 7)/(81 x 13) Â Â Â Â Â = 847/1053
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