please do this problem

Question

RAKESH CHINDAM · Answer

let A 1 , A 2 , A 3 , A 4 ......A n be n Arithmetic means are instead between 20 and 80.
i.e., 20 , A 1 , A 2 , A 3 , A 4 ......A n 80.
∴ The Arithmetic Progression consist of ' n + 2 'terms.
let 'd' be the common difference.
The first term a = 20
The last term L = 80.
but the last term is T n + 2 = a + (n + 2 − 1)d
= a + (n + 1)d
T n + 2 = 80
a + (n + 1)d = 80
20 + (n + 1)d = 80
(n + 1)d = 60
d=60/n+1
Given that the ratio of the first mean to the last mean is 1:3
i.e.,A1/An=1/3

20 + d/20 + nd=1/3
(A n = T n + 1 = a + nd)
20 +60/n+1/20+n.60/n+1
3(n + 4) = (4n + 1)
3n + 12 = 4n + 1
n = 11.

T.kumar · Answer

hi bollu srinivas.. The Arithmetic Progression consist of ' n + 2 'terms.let 'd' be the common difference.The first term a = 20The last term L = 80.but the last term is T n + 2 = a + (n + 2 − 1)d= a + (n + 1)dT n + 2 = 80a + (n + 1)d = 8020 + (n + 1)d = 80(n + 1)d = 60d=60/n+1

SAI SARDAR · Answer

Srinivas, The solution of above question is 11.It is from you can do the problem by the formula of arithematic mean and take ratio.

Ankit Jaiswal · Answer

hi Srinivas, The solution of above question is 11.It is from you can do the problem by the formula of arithematic mean and take ratio.

manmath · Answer

hii let A 1 , A 2 , A 3 , A 4 ......A n be n Arithmetic means are instead between 20 and 80. i.e., 20 , A 1 , A 2 , A 3 , A 4 ......A n 80. ∴ The Arithmetic Progression consist of ' n + 2... yes or no

manmath · Answer

let A 1 , A 2 , A 3 , A 4 ......A n be n Arithmetic means are instead between 20 and 80.
i.e., 20 , A 1 , A 2 , A 3 , A 4 ......A n 80.
∴ The Arithmetic Progression consist of ' n + 2 'terms.
let 'd' be the common difference.
The first term a = 20
The last term L = 80.
but the last term is T n + 2 = a + (n + 2 − 1)d
= a + (n + 1)d
T n + 2 = 80
a + (n + 1)d = 80
20 + (n + 1)d = 80
(n + 1)d = 60
d=60/n+1
Given that the ratio of the first mean to the last mean is 1:3
i.e.,A1/An=1/3

20 + d/20 + nd=1/3
(A n = T n + 1 = a + nd)
20 +60/n+1/20+n.60/n+1
3(n + 4) = (4n + 1)
3n + 12 = 4n + 1
n = 11.

Thank you for registering.

Register Now and Win Upto 25% Scholorship for a Full Academic Year !

Enter Your Details

Registration done!

Guest

please do this problem

please do this problem

6 Answers

Think You Can Provide A Better Answer ?

Other Related Questions on Magical Mathematics[Interesting Approach]

View courses by askIITians

Design classes One-on-One in your own way with Top IITians/Medical Professionals

Complete Self Study Package designed by Industry Leading Experts

Live 1-1 coding classes to unleash the Creator in your Child

a Complete All-in-One Study package Fully Loaded inside a Tablet!

Register Now & Win Upto 25% Scholorship

Thank you for registering.

Register Now and Win Upto 25% Scholorship for a Full Academic Year !

Enter Your Details

Registration done!

Guest

IIT JEE Courses

One Year IIT Programme

Two Year IIT Programme

Crash Course

NEET Courses

One Year NEET Programme

Two Year NEET Programme

One to One

School Board

Live Online classes

Class 11 & 12

Class 9 & 10

Class 6, 7 & 8

Test Series

JEE test series

NEET test series

C.B.S.E test series

Complete Self Study Packages

FULL COURSE

For class 12th

For class 11th

please do this problem

please do this problem

6 Answers

Think You Can Provide A Better Answer ?

Other Related Questions on Magical Mathematics[Interesting Approach]

View courses by askIITians

Design classes One-on-One in your own way with Top IITians/Medical Professionals

Complete Self Study Package designed by Industry Leading Experts

Live 1-1 coding classes to unleash the Creator in your Child

a Complete All-in-One Study package Fully Loaded inside a Tablet!

Register Now & Win Upto 25% Scholorship