Question 103762
Let D = number of DVD sold, and V = number of VHS sold.
If D = V, the store would have sold the same number of each.
If 3D = V, the store would have sold 3 times as many VHS as DVD. Think about this fo a second, since it may look odd. But if they sold 300 VHS, then D=100 to make the equation work.
That leads us to D = 3V, which means the number of DVD sold = 3 times the number of VHS sold.
But, we're told the store wants to sell "at least" 3 times as many, so the store wants D > 3V.