Find n(A) of the following set A.

a) {110,111,112,113,...,130}
I said 21 am i right or wrong?

b) {(1,2), (110,111), (0, 114)}

Question

Find n(A) of the following set A.

a) {110,111,112,113,...,130}
I said 21 am i right or wrong?

b) {(1,2), (110,111), (0, 114)}

anonymous · Answer

is the second one 3 because there are 3 sets?

anonymous · Answer

$n(A)$ denotes the cardinality of set $A$, I think. So, how many elements are in $A$?

Well, look at $\{110,111,112,113,\dots,130\}$. You can change this set and still have the same cardinality. A good way to change it is to substract $110$ from every element. You get: $\{0,1,2,3,\dots,20\}$. So, $n(A)=21$.

I believe b is $3$ as well, since there are $3$ elements (although they are sets).