Solve:
1 + 4 + 7 + 10 + …. + x = 590
given is an AP whose first term is 1 and d is 3(4 - 1) with a number of terms equal to
To find: the value of x for the given AP
Now for the finding number of terms, the formula is
Hence the sum is given by the formula
Now substituting the values in the above formula
It is given that s = 590, so equating the above expression to 590
Solving we get n is 20 or
Since n cannot be a fraction, so we choose n as 20
x = 58