这道数学题怎么做啊Ifthesumofthreedifferentpositiveintegersa,b,andcis11,whichTWOoffollowingaresufficienttodeterminethevalueofa,b,andc?☐Noneofa,b,andcis1.☐Noneofa,b,andcis4.☐Noneofa,b,andc

Question

这道数学题怎么做啊
If the sum of three different positive integers a, b, and c is 11, which TWO of
following are sufficient to determine the value of a, b, and c?
☐ None of a, b, and c is 1.
☐ None of a, b, and c is 4.
☐ None of a, b, and c is 7.
☐ None of a, b, and c is 8.

Answer 1

选None of a, b, and c is 7.
None of a, b, and c is 8

问题是 a b c 三个不同的正整数加起来等于11，下面那个条件 可以推出另两个的数值
当c=8的时候 11-8=3 因为 a b 是不一样的正整数 a b 只可能是 1和2
当c=7时 11-7=4 a b 是 1和3