ЁЯУв Too many exams? DonтАЩt know which one suits you best? Book Your Free Expert ЁЯСЙ call Now!

    Question

    The stream flows at 2 km/h. A boat takes 1 hour more to

    cover 36 km upstream than it takes to go 40 km downstream. What is the distance the boat can cover in still water in 5 hours?
    A 45 km Correct Answer Incorrect Answer
    B 60 km Correct Answer Incorrect Answer
    C 32 km Correct Answer Incorrect Answer
    D 72 km Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    ATQ,

    Let the speed of the boat in still water = тАШyтАЩ km/h Then, upstream speed = (y тАУ 2) km/h And, downstream speed = (y + 2) km/h According to the question, 36/(y тАУ 2) тАУ 40/(y + 2) = 1 (36y + 72 тАУ 40y + 80)/(y┬▓ тАУ 4) = 1 (тАУ4y + 152)/(y┬▓ тАУ 4) = 1 => тАУ4y + 152 = y┬▓ тАУ 4 => y┬▓ + 4y тАУ 156 = 0 => y┬▓ + 13y тАУ 12y тАУ 156 = 0 => y(y + 13) тАУ 12(y + 13) = 0 => (y тАУ 12)(y + 13) = 0 => y = 12 or -13 Rejecting negative value, Speed in still water = 12 km/h Distance in 5 hours = 12 ├Ч 5 = 60 km

    Practice Next
    More Boats and streams Questions

    Relevant for Exams:

    ask-question