find the sum of all integers between 84 and 790 which are multiple of 5
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integers between 84 and 720 which are multiple of 5
85,90,95,100,105,110,115,120,125,130,135,140,145,150,155,
160,165,170,175,180,185,190,200,205,210,215,220,225,230,235,240,245,250........and so on u can calculate
85,90,95,100,105,110,115,120,125,130,135,140,145,150,155,
160,165,170,175,180,185,190,200,205,210,215,220,225,230,235,240,245,250........and so on u can calculate
astha1238:
thanks
sry i think so my answer is wrong by comparing
i m the student of 9grade i was not known with the method
yeah you are right this your answer is wrong this question is solved by the method of AP and the formula is used equal to S n and it is the question of class 11th orl 10th
Answered by
3
solution:
By Ap:
Ap: 85,90,95....790
a=85
d=5
now total terms :
tn=a+(n-1)d=790
=>85+(n-1)5=790
=>(n-1)5=705
=>n-1=141
=>n=142
now, sum of all 142 terms of these Ap:
Sn=>n/2{2a+(n-1)d}
=>142/2{2×85+(142-1)5}
=>71{170+705}
=>62125
sum=62125
By Ap:
Ap: 85,90,95....790
a=85
d=5
now total terms :
tn=a+(n-1)d=790
=>85+(n-1)5=790
=>(n-1)5=705
=>n-1=141
=>n=142
now, sum of all 142 terms of these Ap:
Sn=>n/2{2a+(n-1)d}
=>142/2{2×85+(142-1)5}
=>71{170+705}
=>62125
sum=62125
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