Quantitative Aptitude – Modern Maths – Progressions – Let x, y, z be three positive real


Quantitative Aptitude – Modern Maths - Progressions – Let x, y, z be three positive real

Slot -1 – Quantitative Aptitude – Modern Maths – Progressions – Let x, y, z be three positive real numbers

Let x, y, z be three positive real numbers in a geometric progression such that x < y < z. If 5x, 16y, and 12z are in an arithmetic progression then the common ratio of the geometric progression is?

a) 5/2
b) 1/6
c) 3/2
d) 3/6

Solution:
Given x,y, z are in GP . let common ratio of this GP is r so y=xr & z=xr^2
Now 5x, 16y and 12z are in A.P. So
12z-16y=16y-5x
32y=12z+5x
32xr=12xr^2+5x
12r^2-32r+5=0
(6r-1)(2r-5)=0
So r=1/6 or 5/2
As given x < y < z so r >1
Thus r = 5/2
Option a) 5/2 is correct

Other posts related to Quantitative Aptitude – Modern Maths

Permutation and Combination – Fundamental Principle of Counting
Permutation and Combination – Distribution of Objects
How to find Rank of a Word in Dictionary (With or Without Repetition)
Set Theory- Maximum and Minimum Values
How to solve questions based on At least n in Set Theory for CAT Exam?
Sequence and Series Problems and Concepts for CAT 2017 Exam Preparation
Basic Probability Concepts for CAT Preparation

Crack CAT with Unacademy!

Use referral code HANDA to get 10% off.

  • Daily Live Classes
  • Live Tests and Quizzes
  • Structured Courses
  • Personalized Coaching