Question

"act" the 3rd and 4th terms of an arithmetic sequence are 13 and 18 respectively what is the 50th term of the sequence

Answer 1

In an arithmetic sequence, the nth term is the first term +(n-1)times the difference
the difference between the 3rd and 4th term is 18-13=5, so d=5
now we need to find out the first term: 13=a1+(3-1)d => a1=3
the 50th term is a1+(50-1)d=3+49*5=248
the 

Answer 2

Answer:

50th term is 248

Step-by-step explanation:

the formula for nth term of arithmetic sequence is

$a_n = a+(n-1) d$

'a' is the first term and d is the constant difference

n is the  nth term

3rd term of arithmetic sequence is 13

Now we plug in 3 for n  in the formula

$a_3 = a+(3-1) d$

$13 = a+2d$ --------> equation 1

Given 4th term is 18

The difference between 3rd and 4th term is common difference 'd'

18 - 13 = 5

so d= 5

Now we plug in 5 for 'd' in $13 = a+2d$

$13 = a+2(5)$

13= a+ 10

subtract 10 from both sides

a= 3

We know a=3, d= 5  Lets find 50th term

$a_n = a+(n-1) d$

$a_{50} = 3+(50-1)5$

$a_{50} = 248$