Algebra practice question

Answer: 13

r + 5 = 2(r − 4) gives r + 5 = 2r − 8, so r = 13.

Common wrong answers

If you answered 3

3 comes from setting r + 5 = 2r + 4 − 8 wrongly.

If you answered 9

9 comes from r + 5 = 2r − 4, forgetting to double the 4.

If you answered 18

18 is Ravi's age in 5 years.

More Algebra questions

• Hard
  For how many integer values of x is −2 < (x − 5)/3 ≤ 1 true?
• Hard
  The system 2x + 3y = 6 and 4x + 6y = k has infinitely many solutions. What is the value of k?
• Hard
  Which of the following is the complete solution set to |x − 4| < 6?
• Hard
  A student has $40 to spend on notebooks costing $4 each and pens costing $2 each, and wants at least 12 items …
• Hard
  What is the least whole number of minutes of international calling in a month for which the total monthly cost…
• Hard
  How many liters of the 30% acid solution did the technician use?