Answer:
The minimum number of boxes of pencils to be ordered is 630 boxes.
Explanation:
Since a pupil uses averagely 9.3 pencils
and a box contains 12 pencils,
the school enrollment is also 812
school's enrollment x average use of pencil per student
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number of pencils in a box
812 x 9.3 = 7551.6
7551.6 /12 = 629.3
Having a total number of 630 boxes of pencils to be ordered.
For a p type of semiconductor we need a dopant which is from 13th group in periodic table
Al , B, Ga, In Tl
So the correct element will be In : Indium
The other elements belongs to 15th group and hence will give n type semiconductor