Math Question and Answers


Question and Answers Forum

All Questions Topic List
Number Theory Questions
Previous in All Question Next in All Question
Previous in Number Theory Next in Number Theory
Question Number 67193 by Rasheed.Sindhi last updated on 23/Aug/19

Commented by Rasheed.Sindhi last updated on 24/Aug/19

$\underline{S ome C ounting P roblems}$ $(a) H o w m a n y r e c t a n g l e s a r e i n t h e$ $a b o v e p i c t u r e ?$ $(b) H o w m a n y r e c t a n g l e s c o n t a i n$ $v e r t e x L ?$ $(c) H o w m a n y r e c t a n g l e s c o n t a i n$ $\overset{―}{G Q} a s a n e d g e ?$
Commented by Tony Lin last updated on 24/Aug/19

$(1) C_{2}^{7} C_{2}^{5} = 210$ $c h o o s e t w o f r o m s e v e n v e r t i c a l l i n e s$ $c h o o s e t w o f r o m f i v e h o r i z o n t a l l i n e s$ $(2) C_{1}^{6} C_{1}^{4} = 24$ $c h o o s e o n e v e r t i c a l l i n e e x c e p t O K$ $c h o o s e o n e h o r i z o n t a l l i n e e x c e p t {B H}_{1}$ $t h e n L w o u l d b e a v e r t e x o f r e c t a n g l e s$ $(3) C_{1}^{4} = 4$ $c h o o s e o n e f r o m J T, I S, H R & F P$ $t h e n G Q w o u l d b e a n e d g e o f r e c t a n g l e s$
Commented by mr W last updated on 24/Aug/19

$n i c e q u e s t i o n a n d n i c e s o l u t i o n!$ ${w h a t}^{'} s t h e a n s w e r i f s q u a r e s a r e$ $n o t a c c e p t e d a s r e c t a n g l e s ?$
Commented by Tony Lin last updated on 24/Aug/19

$C_{2}^{7} C_{2}^{5} - 4 \times 6 - 3 \times 5 - 2 \times 4 - 1 \times 3 = 160$ $a l l - 1 \times 1 ◻ - 2 \times 2 ◻ - 3 \times 3 ◻ - 4 \times 4 ◻$
Commented by mr W last updated on 24/Aug/19

$p e r f e c t s i r!$
Commented by Rasheed.Sindhi last updated on 24/Aug/19

$T h e E a s i e s t A p p r o a c h!$ $T h α n k s S i r T o n y L i n!$
Commented by Rasheed.Sindhi last updated on 24/Aug/19

$You can't use 'macro parameter character #' in math mode$ $l o o k i n g f o r y o u$
Terms of Service
Privacy Policy
Contact: info@tinkutara.com

Question and Answers Forum