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Let the number be (10 x + y)
Then, 10 x + y = 3 * (x + y) (given)
Or, 10 x + y = 3 x + 3 y
Or, 10 x - 3 x = 3 y - y
Or, 7x = 2 y
Or, x = 2 y / 7 ( Eq. 1)
Also, 10 x + y + 45 = 10 y + x ( given)
Or, 10 x - x = 10 y - y - 45
Or, 9 x = 9 y - 45 ( Eq. 2)
Substituting the value of x from (Eq. 1) in (Eq. 2), we have:
9 * 2 y / 7 = 9 y - 45
Or, (9 y ) - (18 y / 7) = 45
Or, 63 y - 18 y = 315
Or, 45 y = 315
Or, y = 7
From (Eq. 1),
x = 2 * 7 / 7 = 2
So, the number is 10 x + y = (10 * 2) + 7 = (20 + 7) = 27
Answer
Check:
Sum of the digits = 2 + 7 = 9
9 * 3 = 27 ✓
Adding 45 to the number 27, we get 72. So, the digits get reversed.
Answer:
I think it's the top left one
Step-by-step explanation:
The correct answer is the first option.
If you want to use elimination, you can sum the two equations for example, so that the x's simplify:
Plug this value for y in one of the equations to derive the value of x:
So, the solution is 
Answer:
B. 30
Step-by-step explanation:
A line is 180 degrees, so when we have 100, we subtract that from 180 to get the interior angle of 80.
A triangle has a sum of 180, so we just subtract 80 and 70 from 180 to get 30.
Hope this helps
Answer:
where
Step-by-step explanation:
