A candidate, appearing for an examination, was asked to find 3/14 of a certain number but mistakenly, he found 3/4 of it. When he cross checked his answer, he found his answer was 150 more than the correct answer. Which number was given in the examination for this calculation?

A. 160
B. 180
C. 240
D. 280

Answer

Correct Answer: D. 280


Detail About MCQs

Let the number be x.

The candidate was asked to find 3/14, i.e. 3/14 of x but mistakenly, he found 3/4 of x, and the difference between these answers = 150

3/4 of x – 3/14 of x = 150
⇒ 3/4 × x − 3/14 × x = 150
⇒ 3x/4 − 3x/14 = 150
⇒ 3x × (1/4 – 1/14) = 150
⇒ 3x (5/28) =150

x = 150 × 28 / 5 × 3 = 280

In the following question, one or two equation(s) is/are given. On their basis you have to determine the relation between x and y and then give answer I. x^2 + 3x + 2 = 0 II. 2y^2 = 5y

A. x < y
B. x > y
C. x ≤  y
D. x = y

Answer

Correct Answer: A. x < y


Detail About MCQs

We will separately solve both equations.

Equation 1:

x2 + 3x + 2 = 0
⇒ x2 + 2x + x + 2 = 0
⇒ x (x + 2) + 1 (x + 2) = 0
⇒ (x + 2) × (x + 1) = 0
⇒ x = -2 or, x = -1

Equation 2:

2y2 = 5y
⇒ 2y2 – 5y = 0
⇒ 2y × (y – 5/2) = 0
⇒ y = 0 or, y = -5/2
Both values of y are positive while both values of x are negative.

∴ y > x

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