PSLE
Three boys, Ken, Roy and Joe had the same number of notes. Ken and Roy each had of mix of $10-notes and $5-notes. Ken had 7 $5-notes while Roy had 20 $5-notes. Joe had only $10-notes.

1. Of the three boys, who had the most money? 
2. What was the difference in the total value of Ken and Roy's notes? 
3. Roy used all his $10-notes to buy a gift. He then had $170 less than Joe. How many $10-notes did Joe have?

(a)
The three boys had the same number of notes.
$5-notes have a lower denomination than $10-notes.

Since Joe had only $10-notes, he had the most money.

(b)
Difference in the number of notes of different values
= 20 - 7
= 13

Difference in the value of $10-notes and $5-notes
= 10 - 5
= $5

Difference in the total value of Ken's and Roy's notes
= 13 x 5
= $65

(c)
Value of $5-notes that Roy had left
= 20 x 5
= $100

Total value that Joe had
= 170 + 100
= $270

Number of $10-notes that Joe had
= 270 ÷ 10
= 27

Answer(s): (a) Joe; (b) $65; (c) 27