Final answer:
Mark's test had 50 questions. This was determined by solving the equation generated from the information that Mark got 14 questions wrong and 72% of the total questions right. The correct answer is option b).
Step-by-step explanation:
The student's question asks how many problems were on Mark's test if he got 14 problems wrong and scored 72%. To find the total number of problems on the test, we need to use the information that 72% represents the percentage of correct answers.
First, we calculate what percent 14 wrong answers represents: Assume the total number of questions is x. The number of correct answers is x - 14 because Mark got 14 problems wrong. The correct answers account for 72% of the total, so (x - 14) / x = 0.72.
By solving the equation: x - 14 = 0.72x, we can find the total number of questions. Subtracting 0.72x from both sides gives us: x - 0.72x = 14, which simplifies to 0.28x = 14. Finally, dividing both sides by 0.28 gives us: x = 14 / 0.28, which simplifies to x = 50.