Question

Tenth term of an arithemetic sequence is 74 and common difference 4

a) what should be added to its 10th term to get 15th term? what is the 15th term?

b) find the fifth term of this sequence

c) find the first term​

Answer 1

Step-by-step explanation:

Formula:

t_{n} = t_{1} + (n-1)dt

n

=t

1

+(n−1)d

59 = t_{n}t

n

- the nth term or could be the last term

3 = t_{1}t

1

- the first term

4 = d - the common difference

? = n - the number of terms, the one we are solving for

(Substitute)

t_{n} = t_{1} + (n-1)dt

n

=t

1

+(n−1)d

59 = 3 + (n -1) 4

59 = 3 + 4n - 4

59 = 4n -1

59 + 1 = 4n

60 = 4n

60 / 4 = 4n /4

15 = n

So, n = 15.

There are 15 terms in the sequence