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Teacher video · 2015 P2 Q17
The answer
(a) Most: Cindy; Least: Beth (b) \(\$2.40\) (c) \(23\)
PSLE 2015 Paper 2 Question 17 · Verified worked solution by the Genius Plus Academy teaching team
What this question tests
This is Question 17 of the PSLE 2015 Paper 2 Mathematics paper. It tests money, in the Number & Algebra strand. It is worth 5 marks: 1 + 2 + 2. Open your copy of the paper at this question, then follow our full worked solution below.
Watch the walkthrough
Teacher video · 2015 P2 Q17
All three had the same number of coins; more ten-cent coins means less money. Cindy (all fifty-cent) had the most; Beth (15 ten-cent coins, the most) had the least.
(b) Amy and Beth differ in 6 coins that are fifty-cent for Amy but ten-cent for Beth: \(6 \times (\$0.50 - \$0.10) = \$2.40\).
(c) After spending all her fifty-cent coins Beth had \(15 \times \$0.10 = \$1.50\). Cindy had \(\$1.50 + \$10 = \$11.50\), all in fifty-cent coins: \(\$11.50 \div \$0.50 = 23\) coins.
Answer: (a) Most: Cindy; Least: Beth (b) \(\$2.40\) (c) \(23\)
Same structure, different costume
Change egg tarts to badges, a tank to two tanks, a ring of card to a folded sheet, and a child sees a brand new problem. The lock underneath is the same, and so is the key. Once a student can name the structure, a whole row of questions that look different start to open the same way.
It is also where marks really leak. Across fourteen years of papers, the marks lost in PSLE math leak at the reading far more than at the arithmetic, which is exactly why recognising the structure fixes them. We call this Lock and Key: name the lock, then the key follows.
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One of the 10 question types
The PSLE keeps testing the same 10 structures. Our PSLE Math Intensive trains the Lock and Key reflex across all ten, with 158 curated questions over two days.
It is a money question from the Number & Algebra strand, worth 5 marks: 1 + 2 + 2.
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