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?	Select.
A) 49 rounds	B) 42 rounds	C) 54 rounds	D) 52 rounds	E) None of these
Explanation :   Let the required number of rounds be x   More radius, less rounds(Indirect proportion)   Hence we can write as   radius14:20}::x:70   ⇒ 14 × 70 = 20x   ⇒ 14 × 7 = 2x   ⇒ x = 7 × 7 = 49. 49 roundsnswer : Option 49 rounds
<result>A</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?