Arithmetic Progressions

Algebra Level 1

Find the value of m m in the arithmetic progression with consecutive terms m , 13 , 3 m − 6 … m,13,3m-6\ldots .


The answer is 8.

Theodore Visvikis by Theodore Visvikis , 21, Greece

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

2 solutions

We can do it by taking common difference but I am doing by Arithmetic mean formula.

⇒ m , 13 , 3 m − 6 , . . . . . \Rightarrow m,13,3m-6,.....

⇒ 3 m − 6 + m 2 = 13 \Rightarrow \dfrac{3m-6+m}{2}=13

⇒ 4 m = 32 \Rightarrow 4m=32

∴ m = 8 \therefore m=\boxed{8}

2 Helpful 0 Interesting 0 Brilliant 0 Confused

We have an arithmetic sequence. So 13 − m = d 13-m=d

and 3 m − 6 − 13 = d 3m-6-13=d

Then 13 − m = 3 m − 19 ⇒ 32 = 4 m ⇒ m = 8 13-m=3m-19 \Rightarrow 32=4m \Rightarrow m=8

2 Helpful 0 Interesting 0 Brilliant 0 Confused

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...