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primary 5 | Maths
| Whole Numbers
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How to do it without using algebra
3 camera and 5 printer is 4280
5 camera and 4 printer is 4620
We try and make the number of printers the same in both cases (which is essentially algebra).
A common multiple of 5 and 4 is 20. We try and multiply the printers to 20.
If 3 cameras and 5 printers is 4280, then 4 sets of this would give 12 cameras and 20 printers 17120.
If 5 cameras and 4 printers is 4620, then 5 sets of this would give 25 cameras and 20 printers 23100.
So now,
12 cameras + 20 printers = 17120
25 cameras + 20 printers = 23100
The difference between the two cases is 13 cameras and the price difference is 5980.
Each camera must have cost 460.
Remember that 3 cameras and 5 printers cost 4280.
3 cameras is 1380. So 5 printers is 2900 and 1 printer is 580.
This technique is known as the elimination method and will be seen again in Sec 2 or Sec 3.
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