Digital SATMath: AlgebraEasy
A technician is calibrating a sensor that measures temperature. The sensor output, S, in millivolts, is related to the temperature, T, in degrees Celsius, by the equation S = 0.5T + 20. If the technician measures an output of 35 millivolts, what is the temperature in degrees Celsius?
- A50
- B40
- C15
- D30
Show answer & explanationAnswer & explanation
Correct answer: D. 30
Substitute S = 35 into the equation S = 0.5T + 20. This gives 35 = 0.5T + 20. Subtract 20 from both sides to get 15 = 0.5T, then divide by 0.5 to find T = 30.
Why the other options are wrong
- A. This would be the result if 0.5T = 25, then T = 25/0.5 = 50. This answer is incorrect.
- B. This would be the result if 0.5T = 20, then T = 20/0.5 = 40. This answer is incorrect.
- C. This would be the result if 0.5T = 15, then T = 15/0.5 = 30. This answer is incorrect.
Solving Linear Equations
A linear equation is an algebraic equation in which each term has an exponent of 1, and the graph of the equation is a straight line. Solving it means finding the value(s) of the variable(s) that make the equation true.
- Involves isolating the variable using inverse operations.
- Operations must be applied to both sides of the equation to maintain equality.
- The goal is to get the variable by itself on one side of the equals sign.
Memory trick: Isolate the variable, step by step, to find its true value.