A garden has 1408 plants in total. If there are x rows and each row contains (x−12) plants, what is the number of rows?
Answer and explanation
Correct answer: 44
From the total number of plants, \(x(x−12)=1408\). Thus, \(x^2−12x−1408=0\). Factoring gives \((x−44)(x+32)=0\), so \(x=44\) or \(x=−32\). A number of rows cannot be negative, so \(x=44\) is valid. Checking: \(44(44−12)=44×32=1408\). For option 40, the total would be \(40×28=1120\), not 1408. Exam tip: In word problems, retain only roots that make sense in the stated situation.
Frequently asked questions
What is the correct answer to this question?
44
Why is this the correct answer?
From the total number of plants, \(x(x−12)=1408\). Thus, \(x^2−12x−1408=0\). Factoring gives \((x−44)(x+32)=0\), so \(x=44\) or \(x=−32\). A number of rows cannot be negative, so \(x=44\) is valid. Checking: \(44(44−12)=44×32=1408\). For option 40, the total would be \(40×28=1120\), not 1408. Exam tip: In word problems, retain only roots that make sense in the stated situation.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Quadratic Equations. Topic: Word Problems and Applications.
Student feedback
Was this question useful?
👍 0 Helpful 👎 0 Not helpful
Yes 0% No 0%
0 responsesStudent Reviews
No published reviews yet.
