The width of a rectangle is 15 cm and the length is 4 times the width. What is the perimeter of the rectangle?
一个长方形的宽是15厘米，长是宽的4倍，这个长方形的周长是多少？
<gadget id="calculator">15 * 4</gadget>
<output>60</output>

<gadget id="calculator">60 + 15</gadget>
<output>75</output>

<gadget id="calculator">75 * 2</gadget>
<output>150</output>

<result>150</result>