AlgebraMediumFive-dollar items from a count and a total
Algebra practice question
A stall sold 20 items, some at 3 dollars each and the rest at 5 dollars each, for a total of 76 dollars. How many 5-dollar items were sold?
Answer: 8
With a three-dollar and b five-dollar items, a + b = 20 and 3a + 5b = 76. Substituting a = 20 − b gives 60 + 2b = 76, so b = 8.
Common wrong answers
- If you answered 12
- 12 is the number of 3-dollar items.
- If you answered 16
- 16 stops at 2b = 16.
- If you answered 15.2
- 15.2 divides 76 by 5.
More Algebra questions
- Medium
A system: 2x + y = 11 and x − y = 1. What is the value of x + y? - Medium
Which of the following describes all solutions to 4x − 9 ≤ 2x + 5? - Medium
A phone's battery percentage is modeled by P = 100 − 8t, where t is the number of hours since it was unplugged… - Medium
If y = 2x − 1 and 3x + y = 14, what is the value of x? - Medium
If |2x − 3| = 7, what is the sum of all possible values of x? - Medium
Line k has equation y = (2/3)x + 1. Which equation represents a line perpendicular to line k?
Not affiliated with the College Board. SAT is a trademark of the College Board.