Whole Number P6

The value of $2, $5 and $10 that was saved by Rebecca was in the ratio of 8 : 10 : 3 respectively. After taking out 3/4 of the $2 notes to pay for the gift, and 18 of the $5 notes for the watch, she has $390 left. Find the value of the $10 notes.


Value
$2   $5   $10
-------------
8   :  10  :  3

8 ÷ 2 = 4

10 ÷ 5 = 2

3 ÷ 10 = 3/10


Number
$2      $5     $10
------------------
4    :   2   :  3/10
40u  :  20u  :    3u              Add u to differentiate it from 18 $5 taken out.
-30u  -18
------------------
10u   20u-18   3u

Value
$2           $5         $10
------------------------
20u  100u - $90   30u

150u --> 390 + 90 = 480
1u --> 480 ÷ 150 = $3.20

30u --> 30 x 3.20 = $96

The value of the $10 notes was $96.