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  • #46
    Originally posted by Indefinable View Post

    4.
    No. The answer is 7.8. You can solve it algebraically or, quite simply:

    30 overs = 150 runs in total
    105 overs = 735 runs in total

    75 overs = 585 runs in total
    Hence, on average, there were (585/75) = 7.8 runs per over.

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    • #47
      Originally posted by Morose View Post
      Correct.
      ===== ===== ===== =====
      In a cricket match the average number of runs in the first 30 overs was five. After a further 75 overs, the average runs per over rose to seven.
      What was the average number of runs per over for the last 75 overs only?

      How did you get 75 overs is 585?

      Oh .. 735-150.

      That makes sense.

      ​​​​​​​I thought it was a word problem since you said we don't require knowledge of cricket.

      So the word "first" has 5 letters, "further" has 7 and then proceeded to speculate that "last" has 4.

      ​​​​​​​

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      • #48
        Originally posted by Indefinable View Post


        How did you get 75 overs is 585?

        Oh .. 735-150.

        That makes sense.

        ​​​​​​​I thought it was a word problem since you said we don't require knowledge of cricket.

        So the word "first" has 5 letters, "further" has 7 and then proceeded to speculate that "last" has 4.

        ​​​​​​​
        No, not at all. It has nothing to do with the number of letters in the words - it’s a weighted average of the two halves that resulted in an average of 7 runs/over; and, if during the first 30 overs the average run was 5/over, then during the latter 75 runs the average had to be 7.8 runs/over to get an overall weighted average of 7.

        ((30/105) x 5) + ((75/105) x X) = 7
        1.42 + 0.71X = 7
        0.71X = 5.58
        X = 7.8

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        • #49
          Originally posted by Morose View Post

          Correct.

          What about the other one?
          60÷48=1.25
          1.25×70=87.5

          60÷45=1.33
          1.33×70=93.1

          93.1-87.5=5.6

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          • #50
            Originally posted by Mintchocchip View Post

            60÷48=1.25
            1.25×70=87.5

            60÷45=1.33
            1.33×70=93.1

            93.1-87.5=5.6
            No, but close. Have another go and this time try a different method of calculating time.

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            • #51
              A helicopter covers its outward journey at 308 mph and it returns over exactly the same distance at 231mph. What was the helicopter’s average speed over the entire journey?

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              • #52
                Originally posted by Morose View Post
                A helicopter covers its outward journey at 308 mph and it returns over exactly the same distance at 231mph. What was the helicopter’s average speed over the entire journey?
                It is no fun if nobody will play the game.

                @abu ‘’abdullaah

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                • #53
                  Originally posted by Abu 'Abdullaah View Post
                  The unlimited time to edit a post should be restricted.
                  Post #51 is for you sir.

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                  • #54
                    Originally posted by Morose View Post
                    A helicopter covers its outward journey at 308 mph and it returns over exactly the same distance at 231mph. What was the helicopter’s average speed over the entire journey?
                    It seems nobody wants to play this game so I will reveal the answer and post no more after this.

                    The average speed would be 264. Workings are as follows:

                    The return journey is completed at a slower speed and hence would take longer to complete, thereby affecting the weighted average speed of the entire journey. Because remember that average speed per unit of time is the distance travelled over the time taken to complete the journey.

                    So, the return journey would take 20 minutes longer to complete or 0.3333 of an hour ((308/231) - 1).

                    Hence, if we assume the outward journey at 308 mph is one unit, then the return journey at 231 mph would be 1.33 - total of 2.33.

                    In this way, we can work out the weighted average speed as follows:

                    ((1/2.33) x 308 mph) + ((1.33/2.33) x 231 mph) = 264mph.

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