Let's look for a pattern.sukhman wrote:What is the sixtieth term in the following sequence? 1, 2, 4, 7, 11, 16, 22...
(A) 1,671 (B) 1,760 (C) 1,761 (D) 1,771 (E) 1,821
term1 = 1
term2 = 1 + 1
term3 = 1 + 1 + 2
term4 = 1 + 1 + 2 + 3
term5 = 1 + 1 + 2 + 3 + 4
term6 = 1 + 1 + 2 + 3 + 4 + 5
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.
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term60 = 1 + 1 + 2 + 3 + 4 + . . . 58 + 59
So, we need to evaluate 1 + 2 + 3 + 4 + . . . 58 + 59
Nice rule: The sum of the integers from 1 to n inclusive = (n)(n+1)/2
So, the sum of the integers from 1 to 59 = (59)(60)/2 = 1770
This means that term60 = 1 + 1770
= 1771
= D
Cheers,
Brent
