Sarah had some money in the piggy bank. On Monday, she took out 2/5 of the money to buy a present. She had $78 left and she put it back into the piggy bank. On Tuesday, she took out 3/8 of the money to buy some story books. She had $28.80 left and she put it back into the piggy bank. After that, she found that there was $246.30 in the piggy bank. How much money did she have in the piggy bank at first?

Let initial amount in piggy bank be A
After taking out , she had  remaining
Since the remainder from the , was $78, then after placing the $78 back, there was  in the piggy bank

On Tuesday,  of remainder was taken out leaving  of remainder or 

     After placing the $28.80 back into the piggy bank, she then had 

  Since the final amount in the piggy bank was $246.30, we then get:  
                                                                                 3A = 1,740 - 390 -------- Multiplying by LCD, 8
                                                                                 3A = 1,350
                                                Initial amount in piggy bank, or