Question P6 Constant part
Today’s problem — free all day, every step. Every day has one.
A farm had 150 more chickens than ducks. After 90 ducks were sold at the market, the ratio of the number of ducks to the number of chickens was 1 : 4. How many chickens were there?
Answer
There were 320 chickens.
The ratio changes, but one person's amount stays the same.
In this one. The chickens are never sold, so the gap between the two never closes — it only grows, by exactly the 90 ducks that left, and it is that 240 the ratio has to account for.
A ratio changes and the question tells you only one person gained or lost an amount, while the other kept what they had.
Children keep the same number of shares for the person whose amount did not change. The amount stays the same, but the size of a share can differ between the two ratios.
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