Problem solving

Question

Mia had some pens. She gave 1/3 of her pens plus 1 to her brother. Then, she gave 1/3 of the remaining pens plus 4 to her sister. Finally, she gave 1/2 of what remained plus 3 pens to her bestfriend. She found out the she has 4 pens left. How many pens did Mia have at first?

Answer 1

Start at the end.  If you start from the beginning, you will have a mess!

 

1/2 of the remainder = 4  + 3, that is she had 14 and gave 10 to her best friend

then

2/3 of the remainder = 14 + 4, that is she had 27 and gave 13 to her sister

then

2/3 of the original amount = 27 + 1  that is she had originally 42 pens and gave 15 to her brother