Elimination Method

A question sent in by Jared

Mrs Goh had a sum of money. If she bought 32 apples and 9 pears, she would have $10.40 left. If she bought 12 apples and 24 pears, she would have $14.40 left. Given that she had $30, how many apples could she buy?

Solution:

P4 Question (Model)

Thanks Irene for sending in this P4 question. 

Question:

Patricia bought 2 bicycles n 5 tricycles. She paid $140 more for 5 tricycles than for 2 bicycles. If 2 bicycles cost as much as 3 tricycles, find the total cost of 1 bicycle n 1 tricycle.

Solution:

2 bicycles = 3 tricycles

changes all bicycles to tricycles in the model as followings:

A simple P4 Question using Model

Question: 

Rachel had $80 more than Mary. If Mary gave Rachel $10, Rachel would have thrice as much as money as Mary. How much did they have altogether at first?

Solution: