Question

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

Answer 1

20

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

`2a+d=4 \\ a+9d=19`

Upon solving the system of equation we have:

`a=1 \\ d=2`

Since:

fifth term = a+4d

sixth term = a+5d

The final answer is:

fifth term + sixth term =
`2a+9d=2+18=20`