Sum of integers between 1 to 100 divisible by 2 or 5
Answers
Answered by
83
2=2+4+6+…100 = 50/2*(2+100)=2550
5=5+10+15+…100 =20/2*(5+100)=1050
You may think the answer is 2550+1050=3600 but this is wrong.
2+4+6+…100 and 5+10+15+…100 have common terms.
They are integers divisible by 10, and their sum is
10=10+20+30+…100=10/2*(10+100)=550
Therefore, the answer for this question is 2550+1050-550=3050.
Answered by
16
Answer:
Step-by-step explanation:
2=2+4+6+…100 = 50/2*(2+100)=2550
5=5+10+15+…100 =20/2*(5+100)=1050
You may think the answer is 2550+1050=3600 but this is wrong.
2+4+6+…100 and 5+10+15+…100 have common terms.
They are integers divisible by 10, and their sum is
10=10+20+30+…100=10/2*(10+100)=550
Therefore, the answer for this question is 2550+1050-550=3050
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