Final answer:
To find the unknown number in the equation ? ÷ 2/5 = 4, we can multiply both sides by the reciprocal of 2/5 and then solve for the unknown.
Step-by-step explanation:
The equation that represents the situation is: ? ÷ 2/5 = 4. This equation asks what number divided by the fraction 2/5 equals 4. To solve this equation, we can multiply both sides by the reciprocal of 2/5, which is 5/2. This gives us: (? ÷ 2/5) x (5/2) = 4 x (5/2). Simplifying, we get: ? x (5/2) = 20/2, which further simplifies to: ? x (5/2) = 10. Finally, dividing both sides by 5/2, we find: ? = 10 ÷ (5/2), which equals ? = 10 x (2/5), giving us the final answer: ? = 4.