Factors of 15: 1, 3, 5, 15
<span>Factors of 45: 1, 3, 5, 9, </span>15, 45
<span>The Greatest common factor is 15.</span>
As an opportunity to respond to people who might disagree with your claim.
The 4 litres of red has to be 2 parts of the mixture, so each part will be 2 litres. Therefore 3 parts of cream will be 6 litres and the one part of blue will be 2 litres.