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Friday, March 28, 2025

The ratio of length and breadth of a rectangle is 5 : 4. The perimeter of rectangle is 54 cm. Find the area of rectangle.

March 28, 2025 |

Area, General Aptitude, RRB NTPC Exam 27 Jan 2021, Solved

The ratio of length and breadth of a rectangle is 5 : 4. The perimeter of rectangle is 54 cm. Find the area of rectangle.

A180 cm2

B160 cm2

C210 cm2

D280 cm2

Akhilesh Apr 1 '25 at 20:39

correct answer is: option a [180 cm2]
Explanation: Let the length of the rectangle be $5x$ cm and the breadth be $4x$ cm.
The perimeter of the rectangle is given by $2(l+b)$ . Therefore, $2(5x+4x) = 54$ .
This simplifies to $2(9x) = 54$ , or $18x = 54$ .
Dividing both sides by 18, we get $x = 3$ .
Thus, the length is $5x = 5 \times 3 = 15$ cm and the breadth is $4x = 4 \times 3 = 12$ cm.
The area of the rectangle is given by $l \times b = 15 \times 12 = 180$ cm².

Option a: Correct, as the area is calculated to be 180 cm².

Option b: Incorrect, the area is not 160 cm².

Option c: Incorrect, the area is not 210 cm².

Option d: Incorrect, the area is not 280 cm².

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Thursday, January 9, 2020

The diagonal of a rhombus is 8 m and 6 m respectively. Find its area.

January 09, 2020 |

Area, General Aptitude, RRB Non Technical Exam (Secunderabad) 2016, Solved

The diagonal of a rhombus is 8 m and 6 m respectively. Find its area.

A48 sq.m

B24 sq.m.

C12 sq.m.

D96 sq.m.

rahul Jan 12 '2020 at 9:51

Correct anwer is: 24 sq.m.

Explanaton:

We know that,

Area of a rhombus with diagonals d1 and d2 = $\frac{d1\times d2}{2}$

⇒ Area of rhombus = $\frac{8× 6}{2} = \frac{48}{2} = 24 \text{ sq. m.}$

∴ Area of rhombus = 24 sq. m.

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The perimeter of a triangle is 28 cm. If the length is 5/2 times its breadth, find the length and breadth of the triangle.

January 09, 2020 |

Area, General Aptitude, Lines And Angles, RRB Non Technical Exam (Secunderabad) 2016, Solved

The perimeter of a Rectangle is 28 cm. If the length is 5/2 times its breadth, find the length and breadth of the rectangle.

A9 & 5

B10 & 4

C6 & 7

D11 & 3

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Tuesday, January 7, 2020

The radius of the wheel of a vehicle is 70 cm. The wheel makes 10 revolutions in 5 seconds. The speed of the vehicle is-

January 07, 2020 |

Area, General Aptitude, RRB ASSISTANT LOCO PILOT (Patna) 2013, Solved

The radius of the wheel of a vehicle is 70 cm. The wheel makes 10 revolutions in 5 seconds. The speed of the vehicle is-

A29.46 km/ hr

B31.68 km/ hr

C36.25 km/ hr

D32.72 km/ hr

raju Jan 8 '2020 at 10:50

Correct answer is : 31.68 km/hr

Explanation:

Circumference = 2πr
$= 2 \times \frac{22}{7} \times \text{70 cm}$
= 440 cm

Distance travelled in 10 revolutions = 440 x 10 cm
= 4400 cm
= 44 m

$\therefore Speed = \frac{distance}{time}$

$= \frac{44}{5} \text{ m/sec}$

$= \frac{44}{5} \times \frac{18}{5} \text{ km/hr}$

$= 31.68 \text{ km/hr}$

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The length of a rectangle is increased by 60%. By what percent would the width have to be decreased to maintain the same area ?

January 07, 2020 |

Area, General Aptitude, Percentage, Ratio and Proportion, RRB ASSISTANT LOCO PILOT (Patna) 2013, Solved

The length of a rectangle is increased by 60%. By what percent would the width have to be decreased to maintain the same area ?

A37(1 / 2)%

B0.6

C0.75

DNone

rahul Jan 15 '2020 at 9:30

Correct answer is: $37 \frac{1}{2} \%$

Explanation:

Let original length = x and
original breadth = y.
Then, original area = xy

New length = $\frac{160x}{100} = \frac{8x}{5}$ .
Let new breadth = zThen. $\frac{8x}{5} \times z = xy => z = \frac{5y}{8}$
\therefore Decrease in breadth = $\Big(\frac{3y}{8} \times \frac{1}{y} \times 100 \Big) \% = 37\frac{1}{2}\%$

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