Question 17

loading...

Prev/Next links

Jambmaths question: 

The 3rd term of an A.P is 4x – 2y and the 9th is 10x – 8y. Find the common difference. 

Option A: 

19x – 17y

Option B: 

8x – 4y

Option C: 

x

Option D: 

2x

Jamb Maths Solution: 

$\begin{align}  & {{T}_{3}}=4x-2y---(i) \\ & {{T}_{9}}=10x-8y---(ii) \\ & {{T}_{3}}=a+2d----(iii)\text{    }\text{ }\!\!\{\!\!\text{ }{{T}_{n}}=a+(n-1)d\} \\ & {{T}_{9}}=a+8d----(iv) \\ & {{T}_{9}}-{{T}_{3}}=(10x-8y)-(4x-2y)=6x-6y---(v) \\ & {{T}_{9}}-{{T}_{3}}=6d------(vi) \\ & \text{Equating }(v)\text{ and }(vi) \\ & 6d=6x-6y \\ & d=x-y \\\end{align}$

Jamb Maths Topic: 
Year of Exam: