CTET Solved Paper - RTET Feburary 2011 Paper2
91. The factors of expression (x2 - 2xy + y2 ) - Z2
are
- Option : B
- Explanation : (x2 - 2xy + y2) - z2
= (x - y)2 - z2.
AS ( a - b)2 = a 2 + b2 - 2ab
= (x - y - z) (x - y + z).
a2 - b2 = (a + b)(a - b)
- Option : C
- Explanation : Let (x-2)/x be the fraction. (x-2-2)/(x+2)(x+2)=1/3 Then, 3x - 12 = x + 2. or x = 7. The fraction is 5/7.
93. If we divide x4 - y4 by x - y, then the
quotient and remainder are respectively
- Option : A
- Explanation :
xn _ yn =
(x - y)(xn-1 + xn-2.y+ xn-3y2,
+ ...... + xyn-2 + yn-1).∀ n ∈ N.
x4 - y4 = (x - y)
(x3 +x2y+xy2+y3).
So, Quotient
=(x3 + x 2y + xy2 + y3);
Remainder = 0
94. If the arithmetic mean and geometric mean of two numbers a and b are equal, then
- Option : D
- Explanation : AM ≥ GM
The equality holds when a = b.
AM =(a + b)/2 = (a + a)/2 = a.
GM = √ab = √a2 = a
- Option : B
- Explanation : Given, a beginning amount 'P', the ending amount 'A' after '( number of years can be calculated as A = P (1 + _r_Y" lOOn) Where, r is the interest rate. and n is the number of compounding 111 a year. [ 100 )2,3/2 ff c!'(~ A = 48000 1 + ._-- 2 x 100
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