A man earns a profit of 45 percent by selling a bike for a certain price. If he sells that bike at double the price, then what will be the profit percentage?

Sure, let's solve this step by step.

Step 1: Let's assume the cost price of the bike is 100 units (this could be in any currency but we're using a unitless measure for simplicity).

Step 2: Given that the man earns a profit of 45 percent, this means the selling price of the bike is 145 units (100 units cost price + 45 units profit).

Step 3: If he sells the bike at double the price, the new selling price becomes 2 * 145 = 290 units.

Step 4: The profit earned when the bike is sold for 290 units is 290 units - 100 units (cost price) = 190 units.

Step 5: To find the profit percentage, we use the formula:

Profit Percentage = (Profit / Cost price) * 100

Substituting the values we get:

Profit Percentage = (190 / 100) * 100 = 190%

So, if the man sells the bike at double the price, his profit percentage will be 190%.