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Secondary 1 | Maths
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Please help! My math WA2 is tomorrow and I need to clear my doubts
So the middle one is x + 2 and biggest one is x + 4.
When rounded off to1 s.f , their sum is 200
x + x + 2 + x + 4 = 200 (1 s.f)
3x + 6 = 200 (1s.f)
So smallest possible sum is 150.
(Since 50 to 149 will be rounded to 100)
When 3x + 6 = 150,
3x = 150 - 6
3x = 144
x = 144 ÷ 3
x = 48
Smallest possible numbers are 48,50,52.
The largest possible integer that is rounded to 200(1s.f) would be 249.
But, the sum of 3 even numbers will also be an even number. So we cannot consider 249.
And we cannot consider 248 , the next biggest number (even though 248 is an even number) because :
3x + 6 = 248
3x = 248 - 6
3x = 242
x = 242 ÷ 3
x = 80 R 2
The number is 3x + 6 = 3(x + 2).
So it has to be a multiple of 3. But 248 is not a multiple of 3 and is not divisible by 3.
So we look at the next biggest even number 246.
3x + 6 = 24y
3x = 246 - 6
3x = 240
x = 240 ÷ 3
x = 80
Largest possible numbers are 80,82,84.
Then the smallest one will be x - 2 and the largest will be x + 2.
Their sum is
x - 2 + x + x + 2 = 3x
Then consider 3x = 150 (smallest possible sum)
x = 50
and 3x = 246 (largest possible sum)
x = 82
You will get the same results as previously.
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