1. If tan A = cot A = x , then the value of x is?
A. [latex]\frac{1 + 2 {cos}^{2} A}{sin A cos A}[/latex]
B. [latex]\frac{{sin A cos A}}{1 - 2 {cos}^{2} A}[/latex]
C. [latex]\frac{{sin A cos A}}{1 + 2 {cos}^{2} A}[/latex]
D. [latex]\frac{1 - 2 {cos}^{2} A}{sin A cos A}[/latex]
Answer: Option D
Explanation: tan A - cot A = x
[latex]\frac{sin A}{cos A}[/latex] - [latex]\frac{cos A}{sin A}[/latex] = x
[latex]\frac{{sin}^{2} A - {cos}^{2} A}{sin A cos A}[/latex] = x
[latex]\frac{1 - 2 {cos}^{2} A}{sin A cos A}[/latex] = x
2. What is equation of the line passing through the point (-1, 3) and having x- intercept of 4 units?
A. 3x - 5y = 12
B. 3x + 5y = 12
C. 3x - 5y = - 12
D. 3x - 5y = - 12
Answer: Option B
Explanation: Slope = [latex]\frac{{y}_{2} - {y}_{1}}{{x}_{2} - {x}_{1}}[/latex]
= [latex]\frac{(0 - 3)}{(4 - (-1))}[/latex]
= [latex]\frac{- 3}{5}[/latex]
Equation of line ⇒ (y - 0) = [latex]\frac{- 3}{5}[/latex](x - 4)
5y = -3x + 12
⇒ 3x + 5y = 123
3. 25% discount is offered on an item. By applying a promo code the customer wins 8% cash back. What is the effective discount?
A. 35.75%
B. 35%
C. 31%
D. 12.5%
Answer: Option C
Explanation: Effective Discount = D1 + D2 - [latex]\frac{D1 × D2}{100}[/latex]
= 25 + 8 - [latex]\frac{25 × 8}{100}[/latex]
= 31%
4. Prabhat has done [latex]\frac{1}{2}[/latex] of a job in 12 days. Santosh completes the rest of the job in 6 days. In how many days can they together do the job?
A. 12 days
B. 4 days
C. 8 days
D. 16 days
Answer: Option C
Explanation: Prabhat has done [latex]\frac{1}{2}[/latex] of a job in 12 days
∴Prabhat will do 1 work in 12 x 12 = 24 days.
Similarly, Santosh will do 1 work in 12 days.
No of days work required to complete the work together = [latex]\frac{1}{24}[/latex] + [latex]\frac{1}{12}[/latex]
= [latex]\frac{1 + 2}{24}[/latex]
= [latex]\frac{3}{24}[/latex]
= [latex]\frac{1}{8}[/latex]
∴ Required Time = 8 days
5. x and y are two numbers such that their mean proportion is 16 and third proportion is 128. What is the value of x and y?
A. 8 and 16
B. 16 and 32
C. 8 and 32
D. 16 and 16
Answer: Option C
Explanation: [latex]\frac{x}{y}[/latex] + [latex]\frac{y}{128}[/latex]
⇒ [latex]{y}^{2}[/latex] = 128x ----------- (1)
And, [latex]\sqrt{xy}[/latex] = 16 ----------- (2)
⇒ xy = 256 from (1) and(2) x = 8, y = 32