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At a certain school boys represent 21 pupils less than 58% of the total school,and girls represent 3 pupils more than 46%. How many pupils attend the school?
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Let x be (an unknown) number of pupils in the school.
Then the number of boys is b = 0.58x - 21.
The number of girls is g = 0.46 + 3, according to the condition.
Obviously, b + g = x, and it gives you an equation
0.58x - 21 + 0.46x + 3 = x.
Simplify and solve it for x:
1.04x - 18 = x,
1.04x - x = 18,
0.04x = 18,
x = = = 450.
Answer. The number of pupils in the school is 450.