ACT (Enhanced)MathematicsEasy
A botanist is tracking the growth of a plant. The plant's height (h) in centimeters after 'd' days is given by the equation h = 2d + 5. What is the predicted height of the plant after 10 days?
- A25 cm
- B15 cm
- C17 cm
- D20 cm
Show answer & explanationAnswer & explanation
Correct answer: A. 25 cm
Substitute d=10 into the given equation h = 2d + 5. This results in h = 2(10) + 5 = 20 + 5 = 25 cm. The height after 10 days is 25 cm.
Why the other options are wrong
- B. This would be the result if the initial height was 5 and it grew 1 cm/day for 10 days, ignoring the 2d factor.
- C. This would be the result if d was incorrectly used as 6 instead of 10, or another calculation error occurred.
- D. This would be the result if the initial height was 0, or if 5 was subtracted instead of added.
Linear Equation Evaluation
Substituting a given value for a variable into a linear equation to find the corresponding value of another variable.
- Linear equations represent a straight line.
- They often model real-world relationships.
- Evaluation involves a direct substitution and calculation.
Memory trick: Line's Value: Plug it in, find the number!