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Mathematics 7 Online
OpenStudy (mathmath333):

Counting problem

OpenStudy (mathmath333):

\(\large \color{black}{\begin{align} & \normalsize \text{Find the number of natural number solutions of.}\hspace{.33em}\\~\\ & a+2b+c=100 \hspace{.33em}\\~\\ \end{align}}\)

OpenStudy (dan815):

hmm okay

OpenStudy (dan815):

b can be all even numbers

OpenStudy (dan815):

do you know how to solve the simpler version of this problem a+b+c=100

OpenStudy (mathmath333):

do i need to change 2b to d

OpenStudy (dan815):

sry i mean 2b is all even numbers

OpenStudy (mathmath333):

99C2

OpenStudy (dan815):

yeah thats right

OpenStudy (mathmath333):

i meant to use substitution as 2b=d

OpenStudy (dan815):

here is another way u can think about it a+b+b+c = 100 how would you solve this a+b+c+d=100

OpenStudy (mathmath333):

99C3

OpenStudy (dan815):

i think you would solve a+b+c=100 and divide by 2

OpenStudy (dan815):

as all the odd possibilities would not possible

OpenStudy (mathmath333):

u mean 99C2/2

OpenStudy (dan815):

yeah but let me think that might not technically be true we dont know if odd and even solutions that add to 100 is exactly equal or not

OpenStudy (mathmath333):

How about calculatinb a+b1+b2+d=100 and substracting something

OpenStudy (mathmath333):

?

OpenStudy (mathmath333):

what do u mean

OpenStudy (dan815):

ok back

OpenStudy (dan815):

okay well maybe we can go back to the stars and bars method after this but i think we can do it with just sums

OpenStudy (dan815):

no wait there are 101 WAYs actually to add upto 100 when u pick 2b=0

OpenStudy (dan815):

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