Question

find the fifth term of 20, 16, 12....​

Answer 1

Answer:

8,4

Explanation:

20-16=4

16-12=4

12-8=4

8-4=4

Answer 2

Solution!!

The concept of arithmetic progression (AP) has to be used here.

a = 20

d = 16 - 20 = -4

We are asked to find the fifth term.

aₙ = a + (n - 1)d

a₅ = 20 + (5 - 1)(-4)

a₅ = 20 + (4)(-4)

a₅ = 20 - 16

a₅ = 4

Hence, the fifth term of the AP is 4.

Abbreviations used:

a is the first term of an AP.

d is the common difference between the terms.

More information:

a, a + d, a + 2d,... is the general form of AP. The formula which we used to solve this question is to find the nth term of an AP. We can also find the sum of n terms of an AP using Sₙ = n/2[2a + (n - 1)d].