Math Is Fun Forum

balasvce

Member

Registered: 2006-12-20

Posts: 37

solve and explain

18) the series problem.. here k>=2   if   ak = a (k-1) + 4.. and a1= 3.

find the 100th  term

11) set A contains multiple of 6 n set b contains multiples of

8. No. of multiplies in set C which has common multiplies of A

and B.

Stanley_Marsh

Member

Registered: 2006-12-13

Posts: 345

Re: solve and explain

18.ak-a(k-1)=4  , that means it's a sequence , ak=a1+(k-1)d = 3+(k-1)*4=4k-1=399

dont understand the 11th question ,lol

Last edited by Stanley_Marsh (2006-12-21 16:11:01)

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Numbers are the essence of the Universe

balasvce

Member

Registered: 2006-12-20

Posts: 37

Re: solve and explain

18.ak-a(k-1)=4  , that means it's a sequence , ak=a1+(k-1)d = 3+(k-1)*4=4k-1=399

dont understand the 11th question ,lol

hi stanley
can yu explain how yu got 399

pi man

Member

Registered: 2006-07-06

Posts: 251

Re: solve and explain

If I understand your notation currently, this is what you're saying:

That just means that each term is equal to the previous term plus 4.   So the second term is 7 (3+4) and the 3rd term is 11 (7+ 4).   So to get the 100 term you would have to add 4 ninety times to the first term of 3.   3 + (4*99) = 399.

balasvce

Member

Registered: 2006-12-20

Posts: 37

Re: solve and explain

excellent, great guys