PSLE
Three boys, Tom, Ken and Bo had the same number of notes. Tom and Ken each had of mix of $20-notes and $10-notes. Tom had 9 $10-notes while Ken had 20 $10-notes. Bo had only $20-notes.

1. Of the three boys, who had the most money? 
2. What was the difference in the total value of Tom and Ken's notes? 
3. Ken used all his $20-notes to buy a gift. He then had $300 less than Bo. How many $20-notes did Bo have?

(a)
The three boys had the same number of notes.
$10-notes have a lower denomination than $20-notes.

Since Bo had only $20-notes, he had the most money.

(b)
Difference in the number of notes of different values
= 20 - 9
= 11

Difference in the value of $20-notes and $10-notes
= 20 - 10
= $10

Difference in the total value of Tom's and Ken's notes
= 11 x 10
= $110

(c)
Value of $10-notes that Ken had left
= 20 x 10
= $200

Total value that Bo had
= 300 + 200
= $500

Number of $20-notes that Bo had
= 500 ÷ 20
= 25

Answer(s): (a) Bo; (b) $110; (c) 25