Given the problem below what mistake did Bob make in solving the equation? Bob and his friends paid $30 for 3 sandwiches and and 3 bottles of water.
-Each sandwich cost the same amount.
-The bottles of water cost $1.50 each.
The equation 3(x + 1.50) = 30 can be used to determine x, the cost of each sandwich. Bob solved the equation using these steps: 3(x + 1.50) =30
3x + 1.50 = 30
3x = 28.50
x = 9.50