Q. 173.7( 3 Votes )

<span lang="EN-US

Answer :

Given: Increment in speed = 100 km/h


Distance = 1500 km


To find: The original speed


Method Used:


To solve the quadratic equation by factorisation method, follow the steps:


1) Multiply the coefficient of x2 and constant term.


2) factorise the result obtained in step 1.


3) Now choose the pair of factors in such a way that after adding or subtracting(splitting) them


You get coefficient of x.



Explanation:


Given, while boarding an aeroplane, a passenger got hurt and the plane started late by 30 minutes to reach the destination, 1500 km away in time, the pilot increased the speed by 100km/hr.


Let the usual speed be ‘a’.



2 × 1500 × (a + 100 –a) = a2 + 100a


a2 + 100a – 300000 = 0


a2 + 600a – 500a – 300000 = 0


a (a + 600) – 500(a + 600) = 0


(a + 750) (a – 500) = 0


a = 500 km/hr.


Hence the usual speed is 500 km/hr.


Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos
Introduction to Linear Equations in Two VariablesIntroduction to Linear Equations in Two VariablesIntroduction to Linear Equations in Two Variables62 mins
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
caricature
view all courses
RELATED QUESTIONS :

Find the roots ofKC Sinha - Mathematics

Find the roots ofKC Sinha - Mathematics

4x2KC Sinha - Mathematics

Find the roots ofKC Sinha - Mathematics

36x2KC Sinha - Mathematics