If each edge of a cube is increased by 50%, find the percentage increase in Its

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Question
If each edge of a cube is increased by 50%, find the percentage increase in Its surface area
Options
A. 125%
B. 150%
C. 175%
D. 110%

Correct Answer

125%

Explanation

Let the edge = a cm

So increase by 50 % = a + a/2 = 3a/2

Total surface Area of original cube = $6 a^{2}$

TSA of new cube = $6 {(\frac{3 a}{2})}^{2}$ = $6 (\frac{9 a^{2}}{4})$ = $13.5 a^{2}$

Increase in area = $13.5 a^{2} - 6 a^{2}$ = $7.5 a^{2}$

$7.5 a^{2}$ Increase % = $\frac{7.5 a^{2}}{6 a^{2}} � 100$ = 125%

Volume and Surface Area problems

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Options
A. 27months
B. 23months
C. 20months
D. 12months

2. Find the present worth of a bill of Rs.28000 due 2 years at 12% compound interest. Also find the true discount.
Options
A. 300
B. 350
C. 250
D. 275

3. A man buys a watch for Rs1950 in cash and sells it for Rs 2200 at a credit of 1 yr. The rate of interest is 10% per annum. Then he gains or loose how much amount?
Options
A. 50
B. 55
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C. Rs.1316
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Options
A. 36
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7. A right triangle with sides 3 cm, 4 cm and 5 cm is rotated the side of 3 cm to form a cone. The volume of the cone so formed is:
Options
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