Practice Test 4 - GMAT Quantitative

20 questions. Answer them in any order, then submit to see your score and every explanation.

  1. Which of the following values of tt satisfies both ∣t−4∣<3|t-4|<3 and 2t+1>92t+1>9?
  2. The number of bacteria in a culture triples every 4 hours. If there are currently 2,400 bacteria, how many were there 12 hours ago?
  3. A manufacturing machine produces 40 widgets per hour for the first 3 hours of operation and then 60 widgets per hour thereafter. If the machine produced a total of 540 widgets during one continuous run, for how many hours did it operate?
  4. Two runners start together on a 400-meter circular track and move in the same direction. Runner 1 maintains a constant speed of 2.5 meters per second, whereas Runner 2 maintains 3 meters per second. After how many seconds will Runner 2 have completed exactly one full lap more than Runner 1?
  5. Coffee blend X costs $5 per pound and blend Y costs $9 per pound. How many pounds of blend X must be mixed with 6 pounds of blend Y to obtain a mixture costing exactly $7 per pound?
  6. If real numbers xx and yy satisfy ∣x−3∣+∣y+1∣≤4,|x-3|+|y+1|\le4, what is the maximum possible value of x+yx+y?
  7. The inequality x+2x−1≥3\frac{x + 2}{x - 1} \geq 3 is equivalent to which of the following?
  8. The quadratic ax2+bx+c=0ax^2 + bx + c = 0 has discriminant Δ=25\Delta = 25. If the quadratic ax2+bx+(c+6)=0ax^2 + bx + (c + 6) = 0 has discriminant Δ′\Delta', what is Δ−Δ′\Delta - \Delta'?
  9. The 5-digit integer 5k385k38 is divisible by 11. What is the value of the digit kk?
  10. If x2−4x+k=(x−a)2+bx^2 - 4x + k = (x - a)^2 + b for all values of xx, and k=7k = 7, what is the value of a2+b2a^2 + b^2?
  11. Three tasks require 99, 1212, and 1515 days, respectively, to complete one full cycle. If all three tasks begin today, in how many days will they next all begin a new cycle on the same day?
  12. If aa and bb are positive integers such that gcd⁡(a,b)=12\gcd(a,b) = 12 and lcm(a,b)=180\text{lcm}(a,b) = 180, what is the value of abab?
  13. In a data set of 20 values, the mean is 50 and the median is 48. If the 5 largest values are each decreased by 8, what is the new mean?
  14. If x2−1x2=15x^{2}-\dfrac{1}{x^{2}}=15 and x>1x>1, what is the value of x−1x?x-\dfrac{1}{x}?
  15. For x≠3x\neq 3, the expression x3−27x2+3x+9\dfrac{x^{3}-27}{x^{2}+3x+9} simplifies to
  16. An employee receives a 12% salary increase in January, followed by a 15% bonus based on the new salary in March. If the employee's total annual compensation (salary plus bonus) is $64,400, what was the original salary in December?
  17. Machine A can print 300 pages in 8 minutes, whereas Machine B can print the same 300 pages in 12 minutes. Working together, the two machines must print 1,800 pages. If both machines start at the same time but Machine A jams and stops after exactly 12 minutes, for how many additional minutes must Machine B work alone to finish the 1,800-page job?
  18. For how many positive integers k<100k < 100 is k3−k6\frac{k^3 - k}{6} an integer?
  19. What is the least common multiple of 8484 and 120120 ?
  20. Based on the pie chart shown, what is the median number of clients per department?

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