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Chain Rule Questions Answers

  • 8. In a camp, there is a meal for 120 men or 200 children. If 150 children have taken the meal, how many men will be catered to with the remaining meal ?

    1. 38 men
    2. 32 men
    3. 34 men
    4. 30 men
    Answer And Explanation

    Answer: Option D

    Explanation:

    There is meal for 200 children. 150 children have taken the meal.
    Remaining meal is to be catered to 50 children.
    Now, 200 children = 120 men

    So, 50 Children = 120/200 * 50 = 30 men

  • 9. 4 mat-weavers can weave 4 mats in 4 days. At the same rate, how many mats would be woven by 8 mat weavers in 8 days ?

    1. 12
    2. 14
    3. 16
    4. 18
    Answer And Explanation

    Answer: Option C

    Explanation:

    Please always remember, that what exactly we need to calculate before applying chain formula. As in this question we need to find how many mats, RIGHT !
    So we will compare everything with "number of mats"
    As,

    More men, More number of mats (Direct Proportion)
    More days, More number of mats (Direct Proportion)

    So, it can be solved as,

    \begin{aligned}
    \begin{bmatrix}Weavers & 4 & 8 \\Days & 4 & 8 \end{bmatrix} :: 4 : x \\

    => x*4*4 = 8*8*4 \\
    => x = 16
    \end{aligned}

  • 10. In a dairy farm, 40 cows eat 40 bags of husk in 40 days. In how many days one cow will eat one bag of husk ?

    1. 34 days
    2. 40 days
    3. 46 days
    4. 50 days
    Answer And Explanation

    Answer: Option B

    Explanation:

    Less Cows, More days (Indirect Proportion)
    Less bags, Less days (Direct Proportion)

    \begin{aligned}
    \begin{bmatrix}Cows & 1 & 40 \\Bags & 40 & 1 \end{bmatrix} :: 40 : x \\
    => x * 40 * 1= 40 * 1 * 40 \\
    => x = 40
    \end{aligned}

  • 11. 10 men, working 6 hours a day can complete a work in 18 days. How many hours a day must 15 men work to complete the work in 12 days ?

    1. 4 hours a day
    2. 5 hours a day
    3. 6 hours a day
    4. 7 hours a day
    Answer And Explanation

    Answer: Option C

    Explanation:


    More Men, Less Hours {Indirect Proportion}
    Less Days, More Hours {Indirect Proportion}
    \begin{aligned}
    \begin{bmatrix}Men & 15 & 10 \\Days & 12 & 18 \end{bmatrix} :: 6 : x \\
    => x * 15 * 12 = 10 * 18 * 6 \\
    => x = \frac{10*18*6}{15*12} \\
    => x = 6
    \end{aligned}

  • 12. In a hostel, Food was available for 2000 students for 54 days, but after 15 days more students joined hostel and food lasts only for 20 more days. Determine how many students came in hostel ?

    1. 1650
    2. 1700
    3. 1900
    4. 2100
    Answer And Explanation

    Answer: Option C

    Explanation:

    As it is given that food is there for 54 days for 2000 students,
    But after 15 days, remaining food was sufficient for 2000 students for 39 days only ( as 54-15 = 39 )
    Let x number of students came in hostel after 15 days,
    => Total number of students after 15 days = 2000 + x
    => Remaining food was enough for (2000 + x) students for 20 days
    So here is indirect proportion, as more people and less food
    => 2000 : ( 2000 + x ) :: 20 : 39
    => 2000 * 39 = ( 2000 + x ) * 20
    => 3900 = 2000 + x
    => x = 3900 - 2000
    => x = 1900