Question

the sum of the first 53 terms of an arithmetic series is 4 240 while the seventh term is equal to 20. Find the first term on common difference

Answer 1

Sn=4240.....equatn 1
T7=20....equatn 2..
In arithmetic sequnce T7=a+6d therefore ur equation 2 will now be 20=a+6d.....equation 2.make 'a' the subject of the formula and then use TN=a+(n-1)d to solve for d...substitude 20-6d as ur a and ur n is 53 then solve for common difference

Answer 2

Sn=4240.....equatn 1
T7=20....equatn 2..
In arithmetic sequnce T7=a+6d therefore ur equation 2 will now be 20=a+6d.....equation 2.make 'a' the subject of the formula and then use TN=a+(n-1)d to solve for d...substitude 20-6d as ur a and ur n is 53 then solve for common difference...Answers,,ur 'a 'should be -1 nd ur 'd 'should be 7/2

Answer 3

I meant Sn=4240 meaning S53=4240 coz the n is 53

Answer 4

I really don't understand this