Question

afla cardinalul multimii A={n=N , 3/4 < n+1/15 <4/3}

Answer 1

3/4 < (n+1)/15  => 45<4n-4  => 41< 4n  => n> 41/4  
dar 41/4 =10si1/4

(n+1/15)<4/3  => 3n+3 < 60 => 3n<57  deci n<19
Avem conditiile: n>(10 si1/4) si n<19  dar si neN
A ={11,12,13,14,15,16,17,18} 
Card A=8