Measurements ( 21 to 25 )

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Measurements ( 21 to 25 ):


APTITUDE QUESTIONS (MEASUREMENTS):

21. A rectangular field is to be fenced on three sides leaving a side of 10 feet uncovered. If the area of the field is 480 sq feet, how many feet of fencing will be required?

A)    34

B)    40

C)    68

D)    106

E) None of these

View Answer

Answer: option (D)

Explanation:

L = 10ft and lb = 480 sq ft

So, b = 48 ft

∴ Length of fencing = (l + 2b) = (10 + 96) ft = 106 ft.

 

22. A tank is 15 m long, 6 m wide and 3 m deep. The cost of plastering its walls and bottom at 65 paise per sq m is:

A)    Rs. 156.5

B)    Rs. 158.6

C)    Rs. 155

D)    Rs. 140.4

E)    None of these

View Answer

Answer: option (D)

Explanation:

Area to be plastered = [2(l + b) * h] + (l * b)

= {[2(15 + 6) * 3] + (15 * 6)} m2

= ( 126 + 90) m2 = 216 m2

∴ Cost of plastering = Rs. (216 ∗ 100/65 ) = Rs. 140.4

 

23. A towel when bleached, was found to have lost 30% of its length and 20% of its breadth. The percentage of decrease in area is:

A)    30%

B)    32%

C)    36%

D)    28%

E)    None of these

View Answer

Answer: option (C)


Explanation:

Let original length = x and original breadth = y

Decrease in area = xy – (70/100) 𝑥 ∗ (80/100) 𝑦

= (𝑥𝑦 − (14/25)𝑥𝑦)

= (9/25) 𝑥𝑦

∴ Decrease% = (9/25) 𝑥𝑦 ∗ 1/𝑥𝑦 ∗ 100)% = 36%

 

24. A man walked diagonally across a square lot. Approximately, what was the percent saved by not walking along the edges?

A)    20

B)    24

C)    30

D)    33

E)    None of these

View Answer

Answer: option (C)

Explanation:

Let the side of the square(PQRS) be x meters.

Then, PQ + QR = 2x meters

PR = √2x = (1.41x) m

Saving on 2x metres = (0.59x) m

Saving % = (0.59/2𝑥 ∗ 100) % = 30% approx..

 

25. The diagonal of a rectangle is √30 cm and its area is 17 sq cm. The perimeter of the rectangle must be:

A)    9 cm

B)    16 cm

C)    20 cm

D)    41 cm

E)    None of these

View Answer

Answer: option (B)

Explanation:

√(𝑙2 + 𝑏2 )= √30

lb = 17

(l + b)2 = (l2 + b2) + 2lb = 30 + 34 = 64

=> (l + b) = 8

∴ Perimeter = 2(l+b) = 16 cm

 

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