CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon
MyQuestionIcon
Question

Question 5
Determine the AP whose fifth term is 19 and the difference of the eighth term from the thirteenth term is 20.

Open in App
Solution

Let the first term of an AP be "a" and common difference be "d".

Given, a5=19
a5=a+(51)d=19 [an=a+(n1)d]

and a13a8=20
[a+(131)d][a+(81)d]=20 [an=a+(n1)d]
a+4d=19...(i)
a+12da7d=20
5d=20
d=4
Substituting d = 4 in eq. (i), we get;
a + 4(4) = 19
a + 16 = 19
a = 19 - 16 = 3
So, the required AP is : a, a+d, a+2d, a+3d, ...
= 3, 3+4, 3+2(4), 3 +3 (4), …
= 3, 7, 11, 15, ...

flag
Suggest Corrections
thumbs-up
0
BNAT
mid-banner-image