To find this just put 8 over 20 because that is how many red pieces there are divide the equation and you will get 0.4 so I would say the answer is A.
the solution is in the above picture.
There will be 42 in each row with 2 left over
The HCF is the Highest Common Factor of a number in this case 54. This is the highest number times another number which = 54. The HCF for 54 is 18.
