How do you solve 3 3/4a+3+6=87 in multi step equations

If you would like to solve the equation 3 3/4 * a + 3 + 6 = 87, you can do it using the following steps:

3 3/4 * a + 3 + 6 = 87
15/4 * a = 87 - 3 - 6
15/4 * a = 78    /*4/15
a = 78 * 4/15
a = 104/5
a = 20.8

The correct result is 20.8.