Anna and Elsa are helping set up for the Christmas celebration at Magic Kingdom. They have to install 7 million lights for the annual displa

Question

Anna and Elsa are helping set up for the Christmas celebration at Magic Kingdom. They have to install 7 million lights for the annual display. It takes Elsa 14 days to set up the 7 million lights by herself and it takes Anna 11 days to set up the 7 million lights by herself. How long will it take them to do it together?

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Hải Đăng 5 months 2021-08-26T04:54:20+00:00 1 Answers 7 views 0

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    2021-08-26T04:55:32+00:00

    Answer:

    If they work together, they will take 6.16 days.

    Step-by-step explanation:

    Elsa takes 14 days to complete the work.

    So, 1 day work by Elsa is \frac{1}{14}

    Anna takes 11 days to complete the work.

    So, 1 day work by Anna is \frac{1}{11}.

    So, Let if they work together, it would take x number of days.

    So, we can set up equation as

    \frac{1}{14} +\frac{1}{11}=\frac{1}{x}

    Find LCD, which is 154.

    \frac{11}{154} +\frac{14}{154} =\frac{1}{x}

    Simplify

    \frac{25}{154} =\frac{1}{x}

    Cross multiply,

    25x=154

    Divide both sides by 25

    x=6.16 days

    If they work together, they will take 6.16 days.

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