The greatest common factor of the two numbers A and B is 15, the least common multiple is 90, the number of A is 45, what is the number of B.
甲、乙两数的最大公因数是15，最小公倍数是90，甲数是45，乙数是多少．
<gadget id="calculator">90 / 45</gadget>
<output>2</output>

<gadget id="calculator">15 * 2</gadget>
<output>30</output>

<result>30</result>