Solving a challenging PSLE Maths problem using the model approach (1) |
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QN: A farmer has some chickens and ducks. If he sells 2 chickens and 3 ducks every day, there will be 50 chickens left when all the ducks have been sold. If he sells 3 chickens and 2 ducks every day, there will be 25 chickens left when all the ducks have been sold. (a) How many ducks are there? (b) How many chickens are there? SOLUTIONS: The premise of the model constructed below shall be interpreted as such: 1. The number of chickens less 2/3 the number of ducks is equal to 50 animals 2. The number of chickens less 3/2 times the number of ducks is equal to 25 animals.  (a) There are 5 × 6 = 30 ducks (shown) (b) There are 50 + 4 × 5 = 70 chickens (shown) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The above content is an extract from "50 Challenging PSLE Maths Problems" - purchase a copy of the entire e-book HERE.
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YOU MAY WISH TO READ: Mr Frederick Koh's Primary Level Mathematics Worked Problems Set A conversation with Dr Yeap Ban Har It's not just about PSLE. It's about our society's attitude on grades |
