The length of a rectangle is decreased by 10% and its

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The length of a rectangle is decreased by 10% and its breadth is increased by 10%. By what percent is its area changed?

A0%

B1%

C5%

D100%

Nithin K ? Dec 2 '2016 at 23:57

Answer is : 1%

Explanation:

When there is an increase in sides of a figure, the net increase in its area is

\(= x+y+\frac{xy}{100} \%\)

where x and y are length and breadth

given, length x decreased by 10. so, x =  -10.

breadth y increased by 10. so, y = 10.

percent is its area changed
\(= -10 + 10 + \frac{-10 \times10}{100}\% = -1 \%\)

\(\therefore \text{ percent of area decresed by 1%}\)

 

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The sides of a triangle are in the ratio 3:5:7 and its perimeter is 30 cm.

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The sides of a triangle are in the ratio 3:5:7 and its perimeter is 30 cm. The length of the greatest side of the triangle in cm is

A6

B10

C14

D16

ranjith ? Jul 2 '2017 at 11:7

Answer is 14

Explanation:

Let the sides of the triangle be 3x,5x and 7x units.

According to the questions

3x+5x+7x=30

=> 15x = 30

\(x = \frac{30}{15} =2\)

Largest side = 7x

\(= 7 \times 2\)

=14

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A horse is tied to a peg hammered at one of the corner of a rectangular grass field of 40 m by 24 m by a rope 14 m long. Over how much area of the field can the horse graze ?

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A horse is tied to a peg hammered at one of the corner of a rectangular grass field of 40 m by 24 m by a rope 14 m long. Over how much area of the field can the horse graze ?

A154 sq m

B308 sq m

C240 sq m

D480 sq m

ramesh ? Jul 2 '2017 at 10:55

Answer is 154 sq m

Explanation:

Area of part grazed by horse = \(\frac{1}{4}\)

\(\therefore\) Required Area = \(\frac{1}{4}\pi r^2\)

\(= \frac{1}{4}*(3.14)*(14^2) = 153.86 \)

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