converting methods error message
<p>I get this message for the last part of this code for "cost",</p>

<blockquote>
  <p>The method toDoubleString(double, boolean) in the type Convert is not applicable for the arguments (Double, int),</p>
</blockquote>

<p>not sure how to fix this. if i take it out i get this message,</p>

<blockquote>
  <p>The method toLeftPaddedString(String, int) in the type Convert is not applicable for the arguments (Double, int). </p>
</blockquote>

<p>Help, thanks.</p>

<pre><code>public String printSummaryOutput() {
    return Convert.toRightPaddedString(make, 8) + printSummaryOutput() +  
               Convert.toRightPaddedString(model, 11) + Convert.toLeftPaddedString(color, 6) + 
               Convert.toLeftPaddedString(purchaseDate, 10) + Convert.toLeftPaddedString(Convert.toDoubleString(cost, 10));
}
</code></pre>
