Question

Which term of an A.P 16, 11, 6, 1…is -54?

Answer 1

Answer:

15th term.

Step-by-step explanation:

AP = 16, 11, 6, 1...

➸ tₙ = -54

    a = 16

    d = 16 - 11 = -5

We know that tₙ = a + ( n - 1 )d

➸ -54 = 16 + ( n - 1 ) ( -5 )

    -54 = 16 - 5n + 5

    -54 = 21 - 5n

    -5n = -45 - 21

    -5n = -75

     n = $\frac{-75}{-5}$

     n = 15

∴ The 15th term is -54.