Subtracting and multiplying solutions

The Problem The number of boys in a high school senior class is ten less than twice the number of girls. Also, six fewer than half the students in the class have cars. If 202 students own cars, then how many boys are in the class  

Write an equation letting x represent the number of girls. You can solve for the number of boys (to answer the question) after solving the equation for x. The number of boys is represented by 2x - 10, which is ten less than twice the number of girls. Note the order of the subtraction. Next, write the total number of students as girls plus boys x + 2x- 10. Multiply the total by Vi and subtract 6. Set that expression equal to 202. Then simplify the equation and solve for x. 

The solution x = 142 tells you that there are 142 girls in the class. The number of boys is ten less than twice that, so 2(142) - 10 = 284 - 10 = 274 boys. 

You use division in problems when you want to break some total amount of stuff into equal shares. After setting up the division problem, though, the best course of action for solving the equation is usually to get rid of the division operation. Do this by multiplying each term in the equation by some common denominator then solve the simpler equation that s been created. 

The Problem A man bought two apartment buildings for 210,000 apiece. If there are a total of ten apartments in the two buildings, and if the apartments in one of the buildings cost 40,000 more than the apartments in the other building, then what did he pay for the apartments in the two buildings  

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