The probability that randomly selected adult uses smartphone in meetings is p=0.57 and the probability that randomly selected adult doesn't use smartphone in meetings is q=1-p=1-0.57=0.43.
The probability that exactly 23 of 30 use their smartphones in meetings is
[tex]Pr=C_{30}^{23}p^{23}q^{30-23}=\dfrac{30!}{23!(30-23)!}\cdot (0.57)^{23}\cdot (0.43)^7=2,035,800\cdot (0.57)^{23}\cdot (0.43)^7\approx 0.013432.[/tex]
