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primary 5 | Maths
| Whole Numbers
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I don't know how to solve question 3 and 4. Please help.
Date Posted: 4 years ago
Views: 267
Supply of food
= 84 x 12
= 1008 units (scout-days)
Now, only 63 scouts come to share the 1008 units of food.
Number of days the food will last
= 1008/63
= 16
= 84 x 12
= 1008 units (scout-days)
Now, only 63 scouts come to share the 1008 units of food.
Number of days the food will last
= 1008/63
= 16
Assume all questions are answered correctly.
Then the score is 20 x 5 = 100.
If there are 19 correct answers and 1 incorrect answer, the total score
= 19 x 5 - 1 x 2
= 95 - 2
= 93 (minus is to highlight the score penalty)
If there are 18 correct answers and 2 incorrect answers, the total score
= 18 x 5 - 2 x 2
= 90 - 4
= 86
And so on.
Each time a correct answer is replaced by an incorrect answer, the change in the number of marks is 7 (because I lose 5 marks from losing a correct answer and lose a further 2 marks from gaining an incorrect answer).
Since Siti scores 51 marks, Siti is 49 marks away from the maximum marks.
Number of incorrect answers obtained
= 49/7 (49 marks lost divided by 7 marks lost)
= 7
Number of correct answers obtained
= 20 - 7
= 13
Check.
Total score
= 13 x 5 - 7 x 2
= 65 - 14
= 51
Then the score is 20 x 5 = 100.
If there are 19 correct answers and 1 incorrect answer, the total score
= 19 x 5 - 1 x 2
= 95 - 2
= 93 (minus is to highlight the score penalty)
If there are 18 correct answers and 2 incorrect answers, the total score
= 18 x 5 - 2 x 2
= 90 - 4
= 86
And so on.
Each time a correct answer is replaced by an incorrect answer, the change in the number of marks is 7 (because I lose 5 marks from losing a correct answer and lose a further 2 marks from gaining an incorrect answer).
Since Siti scores 51 marks, Siti is 49 marks away from the maximum marks.
Number of incorrect answers obtained
= 49/7 (49 marks lost divided by 7 marks lost)
= 7
Number of correct answers obtained
= 20 - 7
= 13
Check.
Total score
= 13 x 5 - 7 x 2
= 65 - 14
= 51
See 1 Answer
done
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For Q3, the method is actually inverse proportion, since the more people there are, the less number of days they can survive. Key word is "same amount of food". This means there is a constant "k" you need to find. Always remember that inverse proportion is the method to solve all these time questions. For Q4, you get 5 marks for one correct answer. But when you are wrong, not only will you lose 5 marks for not being correct, you also lose another 2 marks. This means for just 1 wrong answer, you get 7 less marks from 100. Since Siti got 51 marks, means she lost a total of 49 marks from 100. So we can easily find the number of questions she got WRONG and eventually find the questions she got CORRECT
Date Posted:
4 years ago
Thank you very much. Now i understand.
Primary school do not use the term “inverse proportion”. Kindly take note.
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