Mixing
In how many ways can you take out four white balls before taking out three black balls?
$begingroup$
In a box, there are five blue and six green balls. In
another box there are seven white and nine black balls. If we
randomly take out a ball from the 1st box and it is blue then we
must take a white ball out from the 2nd box. If we randomly take out
a ball from the 1st box and it is green then we must take a black
ball out from the 2nd box. In how many ways can you take out four
white balls before taking out three black balls?
Source: Bangladesh Math Olympiad Junior Category 2018
Should I count every possible ways or is there is some other way to solve this math?
combinatorics number-theory elementary-number-theory contest-math
asked Jan 15 at 13:30
ShromiShromi
2819
$endgroup$
add a comment |
$begingroup$
In a box, there are five blue and six green balls. In
another box there are seven white and nine black balls. If we
randomly take out a ball from the 1st box and it is blue then we
must take a white ball out from the 2nd box. If we randomly take out
a ball from the 1st box and it is green then we must take a black
ball out from the 2nd box. In how many ways can you take out four
white balls before taking out three black balls?
Source: Bangladesh Math Olympiad Junior Category 2018
Should I count every possible ways or is there is some other way to solve this math?
combinatorics number-theory elementary-number-theory contest-math
asked Jan 15 at 13:30
ShromiShromi
2819
$endgroup$
add a comment |
$begingroup$
In a box, there are five blue and six green balls. In
another box there are seven white and nine black balls. If we
randomly take out a ball from the 1st box and it is blue then we
must take a white ball out from the 2nd box. If we randomly take out
a ball from the 1st box and it is green then we must take a black
ball out from the 2nd box. In how many ways can you take out four
white balls before taking out three black balls?
Source: Bangladesh Math Olympiad Junior Category 2018
Should I count every possible ways or is there is some other way to solve this math?
combinatorics number-theory elementary-number-theory contest-math
asked Jan 15 at 13:30
ShromiShromi
2819
$endgroup$
In a box, there are five blue and six green balls. In
another box there are seven white and nine black balls. If we
randomly take out a ball from the 1st box and it is blue then we
must take a white ball out from the 2nd box. If we randomly take out
a ball from the 1st box and it is green then we must take a black
ball out from the 2nd box. In how many ways can you take out four
white balls before taking out three black balls?
Source: Bangladesh Math Olympiad Junior Category 2018
Should I count every possible ways or is there is some other way to solve this math?
combinatorics number-theory elementary-number-theory contest-math
combinatorics number-theory elementary-number-theory contest-math
asked Jan 15 at 13:30
ShromiShromi
2819
asked Jan 15 at 13:30
ShromiShromi
2819
asked Jan 15 at 13:30
ShromiShromi
2819
asked Jan 15 at 13:30
ShromiShromi
2819
asked Jan 15 at 13:30
ShromiShromi
2819
2819
add a comment |
add a comment |
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