Natalie had some marbles. She gave 1/3 of them to her brother, who kept 12 marbles for himself and gave the rest to 5 friends. If each friend received 7 marbles, how many marbles did Natalie have at first? solve
The five friends received 7 marbles each, so that accounts for 35 marbles. Including the 12 he kept for himself, the brother received 47 marbles from Natalie.
But that was only 1/3 of what she had , so she had
3(47) or 141 marbles to begin with.