Question

Q-
A solid metal cylinder of 10 cm height and 14 cm diameter is melted and re-cast into two cones in the
proportion of 3:4, keeping the height 10 cm. What would be the percentage change in the flat surface area Before & after?​

Answer 1

Step-by-step explanation:

This aptitude practice question appeared in the quantitative reasoning and data interpretation section of the XAT 2015. Question 5 of a total of 33 questions that appeared in this section in XAT 2015. This one is a medium level difficulty question and tests the concept of computing and comparing flat surface areas of cylinders and cones.

Question

Medium Quant

2 concepts

A solid metal cylinder of 10 cm height and 14 cm diameter is melted and re-cast into two cones in the proportion of 3 : 4 (volume), keeping the height 10 cm. What would be the percentage change in the flat surface area before and after?

9%

16%

25%

50%

None of the above

Correct Answer Choice D. The percentage change in the flat surface area is 50%.

Answer 2

Answer:

Heyy ❤✌✌❤

Here's your Answer..

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Let radius of cylinder, cone 1, cone 2 = R, r1, r2 respectively.

Let their volumes be v, v1, v2respectively.

Cylinder is melted and recast into cone 1 & cone 2

So V = v1 + v2.

Ratio of volumes of the two cones v1 : v2 is 3 : 4.

If v1 is 3x, v2 will be 4x

Hence, volume of cylinder V= 7x.

Therefore, The percentage change in the flat surface area is 50%.

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