Find The Value Of 'n' For Which The Nth Term Of Two Ap's:15,12,9....

1.	Find The Value Of 'n' For Which The Nth Term Of Two Ap's:15,12,9.... And -15,-13,-11...... Are Equal?
Answer» GIVEN are the two AP'S: 15,12,9.... in which a=15, d=-3.............(1) -15,-13,-11..... in which a'=-15 ,d'=2.....(2) now using the nth term's formula,we get a+(n-1)d = a'+(n-1)d' substituting the value OBTAINED in eq. 1 and 2, 15+(n-1) x (-3) = -15+(n-1) x 2 =&GT; 15 - 3n + 3 = -15 + 2n - 2 => 12 - 3n = -17 + 2n => 12+17 = 2n+3n => 29=5n => n= 29/5. Given are the two AP'S: 15,12,9.... in which a=15, d=-3.............(1) -15,-13,-11..... in which a'=-15 ,d'=2.....(2) now using the nth term's formula,we get a+(n-1)d = a'+(n-1)d' substituting the value obtained in eq. 1 and 2, 15+(n-1) x (-3) = -15+(n-1) x 2 => 15 - 3n + 3 = -15 + 2n - 2 => 12 - 3n = -17 + 2n => 12+17 = 2n+3n => 29=5n => n= 29/5.

Find The Value Of 'n' For Which The Nth Term Of Two Ap's:15,12,9.... And -15,-13,-11...... Are Equal?

Answer»

GIVEN are the two AP'S:

15,12,9.... in which a=15, d=-3.............(1)

-15,-13,-11..... in which a'=-15 ,d'=2.....(2)

now using the nth term's formula,we get

a+(n-1)d = a'+(n-1)d'

substituting the value OBTAINED in eq. 1 and 2,

15+(n-1) x (-3) = -15+(n-1) x 2

=&GT; 15 - 3n + 3 = -15 + 2n - 2

=> 12 - 3n = -17 + 2n

=> 12+17 = 2n+3n

=> 29=5n

=> n= 29/5.

Given are the two AP'S: