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Question
Find the total number of ways in which six '+' and four '−' signs can be arranged in a line such that no two '−' signs occur together.
Solution
Six '+' signs can be arranged in a row in
Now, we are left with seven places in which four different things can be arranged in 7P4ways.
Since all the four '- ' signs are identical, four '- ' signs can be arranged in
Number of ways = 1
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