Answer:
$177 total
Explanation:
15(4) + 13(9) = x
60 + 117 = x
x = 177
$177
15 students at $4 each
13 teachers at $9 each
total cost = 15 × $4 + 13 × $9
total cost = $60 + $117
total cost = $177
1.6m questions
2.0m answers