The sum of the first and second terms of an AP is 4 the tenth term is 19 find the sum of the fifth and sixth terms

Respuesta :

Answer:

20

Step-by-step explanation:

first term + second term = 4

tenth term = 19

fifth term + sixth term = ?

Since this is an arithmetic sequence:

first term = a

second term = a+d

tenth term = a+9d

Then we have

[tex]2a+d=4 \\ a+9d=19[/tex]

Upon solving the system of equation we have:

[tex]a=1 \\ d=2[/tex]

Since:

fifth term = a+4d

sixth term = a+5d

The final answer is:

fifth term + sixth term = [tex]2a+9d=2+18=20[/tex]