The greatest common factor of two numbers A and B is 5, and the least common multiple is 60. Where the number of A is 15, what is the number of B?
甲、乙两个数的最大公因数是5，最小公倍数是60．其中甲数是15，乙数是多少．
<gadget id="calculator">4 * 5</gadget>
<output>20</output>

<result>20</result>