Question

Which term of the series 20+16+12+.......n is -96

Answer 1

Hey MATE!

20 ,16 , 12 ......

d = 16 - 20 = -4

a = 20

Therefore to find the term where -96 arrives we apply :

$-96 = 20 + (n-1) \: ( - 4) \\ \\ - 96 + 20 = - 4n + 4 \\ \\ - 76 - 4 = - 4n \\ \\ - 80 = - 4n \\ \\ n = \frac{ - 80}{ - 4} \\ \\ n = 20$


Hope it helps

Hakuna Matata :))

Answer 2

Answer:

The 30th term of the series 20 + 16 + 12 + . . . . . . . . + n is - 96.

Step-by-step explanation:

The given series is 20 + 16 + 12 + . . . . . . . . + n

We need to find the term = - 96

From the first second and third term, it is clear that the given series is AP with first term = a = 20

and common difference = d = - 4

We know that for an AP, aₙ = a + (n - 1)d

Therefore, on substituting the values,

- 96 = 20 + (n - 1) (-4)

=> - 96 - 20 = (n - 1)(-4)

=> - 116 = (n - 1) (-4)

=> 29 = n - 1

=> n = 29 + 1

=> n = 30

Therefore, the 30th term of the series 20 + 16 + 12 + . . . . . . . . + n is - 96.