EPFO 2015 English Medium Solved Paper

Question : 53 of 120

Marks: +1, -0

If the radius of a circles reduced by 50%, its area will be reduced by

Solution:

Let the original radfus =

π

Then, the original area =

πr^{2}

According to the question,
New radius =

r×{(100-50)}/100

r/2

Then, new area

=π{(r/2^{})^{2}}

={πr^{2}}/4

∴ Required percentage

={πr^{2}-{πr^{2}}/4}/ {πr^{2}}×100

3/4×100= 75 %

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