J's answer to Vivi's Primary 5 Maths Whole Numbers Singapore question.
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This is a 'difference unchanged' type of question.
Notice that the difference between their amount of money doesn't change, since they spent the same amount. The difference is the same before and after spending.
So Difference = $1197.50 - $543.50 = $654
Now, May had 2.6 times as much money left as Layla. We can say May had 2.6 units of money left and Layla had 1 unit of money left.
2.6 units - 1 unit = 1.6 units
1.6 units = $654
1 unit = $654 ÷ 1.6 = $408.75
Cost of the watch = Layla's amount at first - Layla's amount left
= $543.50 - 1 unit
= $543.50 - $408.75
= $134.75
Notice that the difference between their amount of money doesn't change, since they spent the same amount. The difference is the same before and after spending.
So Difference = $1197.50 - $543.50 = $654
Now, May had 2.6 times as much money left as Layla. We can say May had 2.6 units of money left and Layla had 1 unit of money left.
2.6 units - 1 unit = 1.6 units
1.6 units = $654
1 unit = $654 ÷ 1.6 = $408.75
Cost of the watch = Layla's amount at first - Layla's amount left
= $543.50 - 1 unit
= $543.50 - $408.75
= $134.75
Date Posted:
5 years ago
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