SOLUTION: The first term of an AP is 7, the last term is 77 and the sum is 380. Find the common difference in the series.
Algebra.Com
Question 861184: The first term of an AP is 7, the last term is 77 and the sum is 380. Find the common difference in the series.
Answer by richwmiller(17219) (Show Source): You can put this solution on YOUR website!
S = ½(a + an)n
380= ½(7 + 77)n
380= ½(84)n
380=42n
380/42=n
190/21=n
n = 9.0476
not possible
The number of terms is not a whole number
RELATED QUESTIONS
The first term of an AP is 7. And the last term is 77.and the sum is 380. Find the common (answered by ikleyn)
The first term of an AP is 7, the last term is 77,the sum is 380. Find the common... (answered by richwmiller)
The sum of the first five terms of an AP is 10, the sum of their squares is 380. Find the (answered by ikleyn)
the first and last teem of an AP are 0 and 108.if the sum the series is 702.find d number (answered by Boreal)
The first term of an Ap is 11 while the last term is 144. If the common difference is 7... (answered by mananth)
Find the sum of the series 1+3.5+6+8.5+......+101
Find the sum of the first 23 term of... (answered by Edwin McCravy,ikleyn)
1)
Given that for an AP seventh term=43 and second term=91,find the valves of a,d and... (answered by richwmiller)
The sum of five terms of an AP is 10 and the sum of their squares is 380. Find the first... (answered by ikleyn)
the 6th term of an ap is 29 and 13th term is 64. calculate the first term common... (answered by Fombitz)