4^2+3^2=25
sqrt 25= 5
Answer is 5
50 out of the 80 were adults if you have to round so it would be 5/8 then you just do 8×100 and then 5×180+70÷100 because you're want to do not do not do it
The differences is 7 because I counted.
<h3>Key points :-</h3>
᪥ The formula to find the 31st term is : 
᪥ In the formula,
represents the first term of the sequence.
᪥
is the number of terms, In our case n is 31.
᪥
is the common difference between the terms, In our case d is 4.

<em>Detailed Solution is attached</em>᭄