Arithmetic Prog...

If $$\displaystyle t_{54}$$ an A.P is -61 and $$\displaystyle t_{4}=64$$ find $$\displaystyle t_{10}$$

Find the number of terms in the sequence$$:\ 4,\  12,\ 20,\ .\ .\ .\ 108$$

The sum of the first $$40$$ natural numbers is

If $$ 5, k, 11$$ are in $$AP,$$ then the value of $$k$$ is 

30th term of the A.P. : 10, 7, 4,.........., is :

The sum of the first $$22$$ terms of the A.P. $$8, 3, -2, ..........$$ is 

If $$\displaystyle { a }_{ n }=2n$$ of an A.P., then common difference is :

If 7 th term of AP is 34 and 13th term is 64 then its 18th term is :

The sum of 2 + 4 + 6 + 8 + .......... + 80 is :

The sum of the first $$1000$$ positive integer is