Question

In a pouch of notes, the number of $2, $5 and $10 are in ratio of 5:4:6. 1/5 of the $2-notes and 15 $5-notes are taken out. The remaining notes are worth $541. Find the difference between the value of $10-notes and $2-notes in the end.

Answer 1

$2-notes : $5-notes : $10-notes
5 : 4 : 6
real value 5n : 4n : 6n
1/5 of $2-notes are taken 5n - 1/5 * 5n = 4n
15 of $5-notes are taken 4n - 15
total remaining notes worth $541
4n * $2 + (4n - 15) * 5 + 6n * 10 = 541
8n + 20n - 75 + 60n = 541
88n = 616
n = 7
So $10-notes there are 6n = 6 (7) = 42
and $2-notes there are 4n = 4 (7) = 28
the difference of their values
= $10 * 42 - $2 * 28
= $364