The number of girls in the school is 57 less than 2 times the number of boys in the school. There are 143 girls in the school. How many boys are in the school?

Let x = number of boys

So 2x - 57 is the number of girls

If there are 143 girls;

2x - 57 = 143; add 57 to both sides;

2x = 200 divide by 2 to solve for x;

x = 100, the number of boys in the school

Check: does 2 (100) - 57 = 143, and the answer is yes