Any n-sided convex polygon with more than 3 sides will have n(n-3)/2 diagonals. For instance, let us look at a square. A square has 4 sides and 2 diagonals. Let us apply this formula with n = 4. We get 4(4-3)/2 = 2 diagonals. Here is a question on finding the number of diagonals. If a n-sided convex polygon has 14 diagonals, how many sides does the polygon … [Read more...] about Number of diagonals in convex polygon : GMAT
GMAT PS : Quadratic Equation : Parabola cutting x-axis
Here is a question testing concepts of Quadratic equation and nature of roots of quadratic equation. If y = x2 + dx + 9 does not cut the x-axis, then which of the following could be a possible value of d? I. 0 II. -3 III. 9 A. III only B. II only C. I and II only D. II and III only E. I and III only Correct Answer : Choice C. Values that 'd' could take are 0 or … [Read more...] about GMAT PS : Quadratic Equation : Parabola cutting x-axis
GMAT Problem Solving : Number Properties
This question is an interesting Number Properties Problem Solving GMAT prep question . How many digits does the product of 412 and 523 contain? A. 12 B. 13 C. 23 D. 24 E. 35 The correct answer is choice D. We can rewrite the given numbers as 224 * 523. i.e., 2 * 223 * 523 = 2 * 1023. This is a 24 digit number. … [Read more...] about GMAT Problem Solving : Number Properties
Number Properties : Data Sufficiency
Number Properties is an all time favorite with the GMAT test makers. Especially in the DS avtar, number properties questions could be quite potent.Here is a seemingly innocuous question from Number Properties presented as a DS question.QuestionIs ab positive?(1) (a+b)^2 < (a-b)^2(2) a = bIt is an "Is" question. So, the answer has to be a definite YES or a definite NO. It cannot … [Read more...] about Number Properties : Data Sufficiency
Quadratic Equations : Sum & Product of roots
Quadratic equations are equations of the form ax2 + bx + c = 0. A quadratic equation has two roots. These roots are found either by factorizing the quadratic equation or by using the formula $latex \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}&s=3$ Here is a typical quadratic equation question If m and n are the roots of the quadratic equation x2 - (2 √ 5)x - 2 = 0, the value of m2 + … [Read more...] about Quadratic Equations : Sum & Product of roots