Find the sum of all natural number that are less than 100 and divisibl

1.	Find the sum of all natural number that are less than 100 and divisible by 4
Answer» Number which are divisible by 4 form An AP:4,8,12,16,..... 96First term a = 4Common difference d = 8-4=4Last term l = 96Total Number of terms ==> an\xa0= a\xa0+ (n-1)d=> 96 = 4 +(n-1)4=> 92 = 4n-4=> 96 = 4n=> n = 24Sum of all numbers\xa0Sn\xa0=\xa0{tex}{n\\over 2}[a+l]{/tex}=>\xa0{tex}{24\\over 2}[4+96]{/tex}= 1200

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