# Omar wants to buy chairs for his new office. Each chair costs $12 and there is a flat delivery fee of$10. If he has $80, how many chairs can he buy? ##### 1 Answer Oct 27, 2016 This is of the form $a x + b = c$#### Explanation: $a =$price per chair ($12)
$x =$number of chairs
$b =$delivery fee ($10) Now the problem can be filled in: $12 \cdot x + 10 = 80 \to$(subtract 10 from both sides) $12 \cdot x = 70 \to$(divide by 12) $x = \frac{70}{12} = 5 \frac{10}{12}$So he can buy 5 chairs and have$10 left. He is \$2 short for the 6th chair.