A rope can make 70 rounds of the circumference of a cylinder whose radius of the base is 14cm. how many times can it go round a cylinder having radius 20 cm? Choose the correct choice
A) 42  B) 49  C) 52  D) 59  E) 62
Required number of rounds be x   More radius, less rounds(Indirect proportion)   Hence we can write as   radius 14:20   ::x:70   =14×70=20x   =14×7=2x   x=7×7=49   ANSWER :49
<result>B</result>
A rope can make 70 rounds of the circumference of a cylinder whose radius of the base is 14cm. how many times can it go round a cylinder having radius 20 cm?