There are 48 books distributed to two groups of children. It is known that the second group has 5 more people than the first group. If all the books are distributed to the first group, each person will have 4 books, and there will be surplus; if each person has 5 books, the books are not enough. If there are 4 books per person, there are not enough books, so how many people are there in the second group?
有48本书分给两组小朋友．已知第二组比第一组多5人，若把书全部分给第一组，每人4本，有剩余；每人5本，书不够，又若全给第二组，每人3本，有剩余；每人4本，书不够，那么第二组有多少人．
<gadget id="calculator">10 + 5</gadget>
<output>15</output>

<result>15</result>