Adam has $900 in $5-notes and $20-notes.
There are 2 times as many $5-notes as $20-notes.
- How many notes are there?
- How much is the value of all the $20-notes?
|
$5 |
$20 |
Total |
Number of notes |
2 u |
1 u |
3 u |
Value of notes |
2 x 5 = 10 u |
1 x 20 = 20 u |
30 u |
(a)
Let the number of $20 notes be 1 u.
Number of $20 notes = 1 u
Number of $5 notes = 2 x 1 u = 2 u
Value of $5 notes = 2 u x 5 = 10 u
Value of $20 notes = 1 u x 20 = 20 u
Total value of notes = 20 u + 10 u = 30 u
30 u = 900
1 u = 900 ÷ 30 = 30
Total number of notes
= 2 u + 1 u
= 3 u
= 3 x 30
= 90
(b)
Value of all the $20-notes
= 20 u
= 20 x 30
= $600
Answer(s): (a) 90; (b) $600