1.

Find the sum of all two digits numbers divisible by 4.1). 11882). 11823). 11864). 1184

Answer»

Required NUMBERS are: 12, 16, 20, ……, 96

This is an ARITHMETIC progression series in which FIRST term, a = 12 difference, d = 4 and last term l = 96. LET no. of terms in this series is n.

⇒ l = a + (n – 1) × d

⇒ 96 = 12 + (n – 1) × 4

⇒ (n – 1) × 4 = 84

⇒ n – 1 = 21

⇒ n = 22

∴ required sum = (n/2) × (a + l) = (22/2) × (12 + 96) = 11 × 108 = 1188


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