Digital SAT Math Practice Questions - Advanced : Linear equations in one variable - New Syllabus
DSAT MAth Practice questions – all topics
- Algebra Weightage: 35% Questions: 13-15
- Linear equations in one variable
- Linear equations in two variables
- Linear functions
- Systems of two linear equations in two variables
- Linear inequalities in one or two variables
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DSAT MAth and English – full syllabus practice tests
\[ -2|x-5| = -4x \]
What are all possible solutions to the given equation?
A) -5
B) \(\frac{5}{3}\)
C) -5 and \(\frac{5}{3}\)
D) 5 and \(-\frac{5}{3}\)
▶️ Answer/Explanation
Answer: B
Solving \(|x-5| = 2x\), we get two cases:
Case 1: \(x – 5 = 2x\)
\(x – 2x = 5\)
\(-x = 5\)
\(x = -5\)
Case 2: \(x – 5 = -2x\)
\(x + 2x = 5\)
\(3x = 5\)
\(x = \frac{5}{3}\)
Checking solutions in the original equation \(-2|x-5| = -4x\):
For \(x = -5\):
Left side: \(-2|-5 – 5| = -2| -10 | = -2 \times 10 = -20\)
Right side: \(-4 \times -5 = 20\)
\(-20 \neq 20\), so \(x = -5\) is not a solution.
For \(x = \frac{5}{3}\):
Left side: \(-2|\frac{5}{3} – 5| = -2|\frac{5}{3} – \frac{15}{3}| = -2|\frac{-10}{3}| = -2 \times \frac{10}{3} = -\frac{20}{3}\)
Right side: \(-4 \times \frac{5}{3} = -\frac{20}{3}\)
\(-\frac{20}{3} = -\frac{20}{3}\), so \(x = \frac{5}{3}\) is a solution.
Thus, the only valid solution is \(x = \frac{5}{3}\).
Hector used a tool called an auger to remove corn from a storage bin at a constant rate. The bin contained 24,000 bushels of corn when Hector began to use the auger. After 5 hours of using the auger, 19,350 bushels of corn remained in the bin. If the auger continues to remove corn at this rate, what is the total number of hours Hector will have been using the auger when 12,840 bushels of corn remain in the bin?
A) 3
B) 7
C) 8
D) 12
▶️ Answer/Explanation
Answer: D
Rate of removal = \(\frac{24,000 – 19,350}{5} = 930\) bushels per hour. Using \(24,000 – 930x = 12,840\), solve for \(x\): \(930x = 11,160\), \(x = 12\).
The Townsend Realty Group invested in the five different properties listed in the table above. The table shows the amount, in dollars, the company paid for each property and the corresponding monthly rental price, in dollars, the company charges for the property at each of the five locations.
Property address | Purchase price (dollars) | Monthly rental price (dollars) |
---|---|---|
Clearwater Lane | 128,000 | 950 |
Driftwood Drive | 176,000 | 1,310 |
Edgemont Street | 70,000 | 515 |
Glenview Street | 140,000 | 1,040 |
Hamilton Circle | 450,000 | 3,365 |
Townsend Realty purchased the Glenview Street property and received a 40% discount off the original price along with an additional 20% off the discounted price for purchasing the property in cash. Which of the following best approximates the original price, in dollars, of the Glenview Street property?
A) $350,000
B) $291,700
C) $233,300
D) $175,000
▶️ Answer/Explanation
Answer: B
With a 40% discount and 20% off the discounted price, the final price is 48% of the original. Given \(0.48x = 140,000\), solve for \(x\): \(x = \frac{140,000}{0.48} \approx 291,667\), closest to $291,700.