At this bake sale, Mr. Heftwhistle sold 30% of his pies to one friend. Mr.. Heftwhistle then sold 60% of the remaining pies to another friend. What percent of his original number of pies did Mr. Hefrwhistle have left?

Options

A. `10%`
B. `18%`
C. `28%`
D. `36%`

Answer

To solve the problem step by step, let's denote the total number of pies Mr. Heftwhistle originally had as \( X \).

### Step 1: Calculate the number of pies sold to the first friend.
Mr. Heftwhistle sold 30% of his pies to the first friend.

\[ \text{Pies sold to the first friend} = 30\% \text{ of } X = \frac{30}{100} \times X = 0.3X \]

### Step 2: Calculate the number of pies remaining after the first sale.
After selling 30% of his pies, the number of pies left is:

\[ \text{Remaining pies} = X - 0.3X = 0.7X \]

### Step 3: Calculate the number of pies sold to the second friend.
Mr. Heftwhistle then sold 60% of the remaining pies to the second friend. The remaining pies are \( 0.7X \).

\[ \text{Pies sold to the second friend} = 60\% \text{ of } 0.7X = \frac{60}{100} \times 0.7X = 0.6 \times 0.7X = 0.42X \]

### Step 4: Calculate the number of pies remaining after the second sale.
After selling 60% of the remaining pies, the number of pies left is:

\[ \text{Remaining pies} = 0.7X - 0.42X = 0.28X \]

### Step 5: Calculate the percentage of the original number of pies left.
Now, we need to find out what percent of the original number of pies \( X \) is left. We can express this as:

\[ \text{Percentage left} = \left( \frac{0.28X}{X} \right) \times 100\% \]

Since \( X \) cancels out, we have:

\[ \text{Percentage left} = 0.28 \times 100\% = 28\% \]

### Final Answer:
Mr. Heftwhistle has **28%** of his original number of pies left.

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