Answer: here are 48 adults of this younger age group.
Step-by-step explanation:
Since we have given that
Error = 0.10
p = 23% = 0.23
At 90% level of significance, i.e. α = 0.10
So, the value of z = 1.645
[tex]n=(\dfrac{z}{E})^2p(1-p)\\\\n=(\dfrac{1.645}{0.1})^2(0.23)(1-0.23)\\\\n=270.6025\times 0.23\times 0.77\\\\n=47.92\\\\n\approx 48[/tex]
Hence, there are 48 adults of this younger age group.