Here is an interesting quadratic equations question. Combines some concepts of number theory.Questiony = x^2 + bx + 256 cuts the x axis at (h, 0) and (k, 0). If h and k are integers, what is the least value of b?A. –32B. –256C. –255D. –257E. 0Correct Answer : Choice D. -257ExplanationThe curve cuts the x axis at (h, 0) and (k, 0). So, h and k are the roots of the quadratic … [Read more...] about Quadratic Equation : Sum of Roots
GMAT Number Properties
GMAT Equations, Number Properties
Here is an interesting question that combines linear equations and properties of numbers to get an answer.QuestionA children’s gift store sells gift certificates in denominations of $3 and $5. The store sold ‘m’ $3 certificates and ‘n’ $5 certificates worth $93 on a Saturday afternoon. If ‘m’ and ‘n’ are natural numbers, how many different values can ‘m’ take?A. 5B. 7C. 6D. … [Read more...] about GMAT Equations, Number Properties
Inequalities Data Sufficiency
Inequalities and Data Sufficiency are a great combination. Many interesting questions have been framed in the DS format from this topic. Here is an interesting question Is a < b? 1. a^b < b^a 2. a/b > 1 This is a good question because it helps us consider several possibilities for examples. Let us start with Statement I alone: 1. a^b < b^a Now, if a … [Read more...] about Inequalities Data Sufficiency
Number Properties Data Sufficiency
Here is an interesting data sufficiency question.How many of the numbers x, y, and z are positive if each of these numbers is less than 10?1. x + y + z = 202. x + y = 14Correct Answer : Choice A. Statement 1 alone is sufficient; Statement 2 is not sufficient.Explanatory Answer:Statement 1 : x + y + z = 20. From the question stem we know that each number is less than 10.So, x … [Read more...] about Number Properties Data Sufficiency
GMAT Inequalities – Least integer
Here is an interesting inequalities question.What is the smallest integer that satisfies the inequality ?(x - 3)/ (x^2 - 8x - 20) > 0A. -2B. 10C. 3D. -1E. 0Correct Answer : -1. Choice D Explanatory AnswerLet us factorize the denominator and rewrite the expression as (x - 3) / {(x - 10)(x + 2)}The values of x that are of interest to us are x = 3, x = 10 and x = -2.Let us … [Read more...] about GMAT Inequalities – Least integer