general Maths Puzzle

How many terms of the series 5 + 7 + 9 + …… must be taken in order that the sum may be 480?

Read Solution (Total 1)

20

for n terms of series
5 + 7 + 9 + ...

sum = (n/2 )*(10+(n-1)*2)=480
so n=20
12 years agoHelpfull: Yes(2) No(4)

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