PSLE
Three men, Ben, Lee and Ken had the same number of notes. Lee and Ben each had of mix of $20-notes and $10-notes. Lee had 2 $10-notes while Ben had 12 $10-notes. Ken had only $20-notes.

1. Of the three men, who had the least money? 
2. What was the difference in the total value of Lee and Ben's notes? 
3. Ben used all his $20-notes to buy a souvenir. Ken then had $280 more than Ben. How many $20-notes did Ken have?

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

Ben had more $10-notes than Lee while Ken had only the $20-notes.  

Since Ben had the most number of $10-notes, he had the least money.

(b)
Difference in the number of notes of different values
= 12 - 2
= 10

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

Difference in the total value of Lee's and Ben's notes
= 10 x 10
= $100

(c)
Value of $10-notes that Ben had left
= 12 x 10
= $120

Total value that Ken had
= 280 + 120
= $400

Number of $20-notes that Ken had
= 400 ÷ 20
= 20

Answer(s): (a) Ben; (b) $100; (c) 20