Bradley washed 8 cars. He earned \( \$ 10, \$ 12 \), \( \$ 15, \$ 15, \$ 15, \$ 9 \) and \( \$ 10 \) for 7 cars. How much did he earn the eight time if the mean of the data is \( \$ 12 \) ?

To find out how much Bradley earned for the eighth car, we first need to calculate the total earnings from all eight cars using the mean. The mean is given as \( \$ 12 \), and since he washed 8 cars, we can calculate the total earnings as follows: \[ \text{Total earnings} = \text{Mean} \times \text{Number of cars} = 12 \times 8 = \$ 96. \] Next, we add the earnings he made from the first seven cars: \[ 10 + 12 + 15 + 15 + 15 + 9 + 10 = \$ 96. \] Now, let's sum these amounts: \[ 10 + 12 = 22, \] \[ 22 + 15 = 37, \] \[ 37 + 15 = 52, \] \[ 52 + 15 = 67, \] \[ 67 + 9 = 76, \] \[ 76 + 10 = 86. \] So, the total earnings for the first seven cars is \( \$ 86 \). Now we can find out how much he earned for the eighth car by subtracting this total from the overall total: \[ \text{Earnings from eighth car} = \text{Total earnings} - \text{Total from first seven cars} = 96 - 86 = \$ 10. \] Thus, Bradley earned \( \$ 10 \) for the eighth car.