Samuel had a total of 30 nuggets and fish balls at first. He exchanged all his nuggets for fish balls. He had 48 fish balls after exchanging every 1 nugget for 2 fish balls. How many fish balls did he have at first? (Sam has 30 nuggets and fishballs at first. he exchanged all his nugget for fishballs. he has 48 fishballs after changing every 1 nugget for 2 fishballs. how many fishballs does he has at first?)
Let us assume Sam had x nuggets & fishballs at first.
He had 30 (nuggets + fishballs)
He exchanged every 1 nuggets for 2 fishballs.
He had (30 - x) nuggets at first.
Exchanging all of his nuggets will give him (30 - x) * 2 fishballs.
= 60 - 2x fishballs.
The total number of fishballs he had now (60 - 2x + x) [after exchanging all the nuggets] = 60 - x
By the problem,
60 - x = 48
=> x = 60 - 48
=> x = 12
Sam had 12 fishballs at first.