Question 195392
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Let us see first how many teachers are they for a class size of 30 students per teacher.


{{{(1200cross(students))(1teacher/30cross(students))}}}
{{{red(40teachers)}}}} Original number of teachers



For new class size:
{{{(1200cross(students))(1teacher/24cross(students))}}}
{{{red(50teachers)}}}}  New number of teachers



Therefore, the school needs additional, 50-40 = <font color=blue>10 teachers</font>, Answer