If each of edge of a cube is increased by 75%, then the percentage increase in surface area is :
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Solution
% Increase = 75 + 75 +
= 206.25%
If the measure of three angles of a triangle are in the ratio 2 : 3 : 5, then the triangle is :
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Solution
Let the angles are 2x, 3x & 5x
2x + 3x + 5x = 180°
x = 18°
∴ Angles are 36, 54, 90°
So it is a right anlged triangle.
A is thrice as good as B in work. A is able to finish a job in 60 days less than B. they can finish the work in how many days if they work together ?
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Solution
Given that
3x – x = 2x = 60
x = 30
∴ Required days = days
Find the ratio in which rice at Rs 72 a kg be mixed with rice at Rs 57 a kg to produce a mixture worth Rs 63 a kg :
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Solution
∴ Ratio = 2 : 3
The difference between compound interest and simple interest on an amount of Rs 15000 for 2 years is Rs. 96. What is the rate of interest per annum ?
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Solution
96 = 15000 ×
R = 8%
Cost price of 100 books is equal to the selling price of 80 books. The gain or loss percentage will be :
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Solution
% Gain =
If tan 2θ · tan 4θ = 1 then find the value of tan 3θ :
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Solution
tan 2θ · tan 4θ = 1
∴ 2θ + 4θ = 90
θ = 15°
∴ tan 3θ = 1
Find the value of sin 30° + tan 45° – cos 60° :
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Solution
sin 30° + tan 45° – cos 60° = sin 30° + tan 45° – sin 30°
sin 30° + tan 45° – cos 60° = 1
If x + = 6 then find the value of :
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Solution
⇒ x2 + 1 = 6x
∴
A polygon has 20 diagonals. The number of sides of the polygon is –
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Solution
Let the number of sides is n
∴ 20 =
n = 8