To solve this problem, assign numbers to the circles in a way that the sum of the numbers on each line is equal at both ends. ;
The correct answers are:
Top circle: 34
Bottom left: 9
Bottom right: 21
Explanation :
Let the top circle be x, let the bottom left circle be y, and the bottom right circle be z.
Following the diagram, we have the following equaitons:
x+y = 43
y+z = 30
x+z = 55
Taking the first two equations as a system, we will eliminate y:
{ z + y = 30 x + y = 43
We will subtract the bottom equation from the top:
{ − ( z + y = 30 ) x + y = 43 x − z = 13
We will now take this and the last equation as a system; this time, we will eliminate z by adding the two equations:
{ + ( x + z = 55 ) x − z = 13 2 x = 68
Divide each side by 2:
2x/2 = 68/2
x = 34
Substitute this into the first equation:
x+y = 43
34+y = 43
Subtract 34 from each side:
34+y-34 = 43-34
y = 9
Substitute this into the second equation:
y+z = 30
9+z = 30
Subtract 9 from each side:
9+z-9 = 30-9
z = 21
To solve the problem, we let the numbers in the circles be x, y, and z. We derived the equations x + y = 43 , y + z = 30 , and x + z = 55 , leading to the solutions x=34, y=9, and z=21. Therefore, the numbers in the circles should be 34, 9, and 21 respectively.
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