Question

A jar contains only red and blue sweets in a ratio of 1:3. Kate thinks that 1/3 of the sweets are red.

a) Kate has made a mistake. Explain why she might have made this mistake.
b) What is the correct fraction of sweets that are red?

Answer 1

a) she might have made the mistake as she saw the 1:3 and viewed it as a fraction. 1/3≠1:3

b) the correct fraction of the red sweets is 1/4.

1:3 means that there are 3 blue sweets to every red sweet. This means that there is a minimum of 4 sweets in the jar for this ratio to be true. Out of the 4 sweets, only 1 of them is red while the other 3 are blue.