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The sum of the two positive numbers is 55 and their difference is 19. What are the numbers?
40, 15
36, 19
37, 18
35, 20
37, 18
Add the two numbers and divide by 2 to get the larger number, then subtract the difference from the sum's half or simply subtract the smaller number from the total sum: (55+19)/2=37 and (55тИТ19)/2=18.
Sum of two positive numbers = 55, Difference between the same two numbers = 19
x+y=55,xтИТy=19
Add the two numbers and divide by 2 to get the larger number, then subtract the difference from the sum's half or simply subtract the smaller number from the total sum: (55+19)/2=37 and (55тИТ19)/2=18.
Confusing the order of subtraction leading to negative values or forgetting that the numbers must be positive.
Set up equations
Let the two positive numbers be x and y. Based on the problem, we have two equations: the sum is 55 (x+y=55) and the difference is 19 (xтИТy=19).
x+y=55xтИТy=19
Solve for the first variable
Add both equations together to eliminate y: (x+y)+(xтИТy)=55+19, which simplifies to 2x=74.
2x=74тЯ╣x=37
Solve for the second variable
Substitute the value of x back into the first equation: 37+y=55, so y=55тИТ37=18.
y=18
C is correct because solving the system of equations x+y=55 and xтИТy=19 yields the numbers 37 and 18.
This concept of 'Sum and Difference' is a fundamental technique used in solving ages, speed-distance-time, and mixture problems across all competitive exams.