If you would like to know the values of these two numbers, you can calculate this using the following steps:
a + b = 77.95
a - b = 30.61 ... a = 30.61 + b
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a + b = 77.95
(30.61 + b) + b = 77.95
30.61 + 2 * b = 77.95
2 * b = 77.95 - 30.61
2 * b = 47.34 /2
b = 47.34 / 2
b = 23.67
a = 30.61 + b = 30.61 + 23.67 = 54.28
Result: The numbers are 23.67 and 54.28.