Question : If $a + b = 10$ and $ab = 9$, then the value of $a - b$ is:
Option 1: 7
Option 2: 5
Option 3: 8
Option 4: 6
Correct Answer: 8
Solution : Given: $a + b = 10$ and $ab = 9$ We know that, $(a-b)^2=(a+b)^2-4ab$ Putting the value, we get: ⇒ $(a-b)^2=10^2-4\times9$ ⇒ $(a-b)^2=100-36$ ⇒ $(a-b)^2=64$ $\therefore(a-b)=8$ Hence, the correct answer is 8.
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Question : If a3 + b3 = 217 and a + b = 7, then the value of ab is:
Option 1: – 6
Option 2: – 1
Option 3: 7
Question : If $\cos A = \sin ^2A$, and $a \sin ^{12}A+b \sin ^{10}A+c \sin ^{8}A+ \sin ^{6}A=1$, then $a + b + c$?
Option 2: 8
Option 3: 9
Question : Directions: A series of figures are given which can be grouped into classes. Select from the alternatives one set of groups into which the figures can be classified.
Option 1: 1, 3, 6; 2, 4, 6; 5, 7, 9
Option 2: 1, 4, 9; 3, 6, 8; 2, 5, 7
Option 3: 3, 4, 7; 9, 8, 7; 4, 3, 1
Option 4: 2, 3, 6; 9, 3, 4; 6, 3, 2
Question : If A : B = 3 : 4 and B : C = 6 : 5, then A : ( A + C) is equal to:
Option 1: 9 : 10
Option 2: 10 : 9
Option 3: 9 : 19
Option 4: 19 : 9
Question : If $\frac{2}{3}$ of A = 75% of B = 0.6 of C, then $A:B:C$ is:
Option 1: $2:3:3$
Option 2: $3:4:5$
Option 3: $4:5:6$
Option 4: $9:8:10$
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