一个长方体的地面积是21,另外,其中一个面的面积是30.
问题描述：
一个长方体的地面积是21,另外,其中一个面的面积是30.
请问体积是多少?答案是220.
1,The area of the base of the rectangular box is 21 and the area of one of the faces is 30.Each of the dimensions j,k,and l is an integer greater than 1.What is the volume of the rectangular box?（答案是220）
If n>1 and each of the three integers n,n+2,n+4 is a prime number,then the set of three such numbers is claaed a"prime triple"There are how many different prime triples?（答案是1）
答
1.明显是210,因为21和30只有公因数3,因为每条边整数所以一条边是3,所以长宽高为10,3,7,v=210
2.明显只有一组3,5,7,因为n,n+2,n+4中一定会有一个是3的倍数,而只有3是质数,所以只有1组.