Please help

6 years after Jacob is three times,his current age,he will be the same age as his dad is now.His dad is 39 years old now.How old is Jacob now? 

Multiply Jacob's age by three, then add six.  This will equal dad's age. 

                                                         3J + 6 = 39   

subtract 6 from both sides                3J       = 39 – 6  

                                                         3J       = 33 

divide both sides by 3                         J      = 11 

_.

For this problem you can work backwards. If it is 6 years after Jacob is three times his age. First, subtract 6 from 39. 39 - 6 = 33. Then, divide by 3,     33÷3 = 11. So his age is 11.