Answer:
A: Y = X + 2.5
B: 10
Step-by-step explanation:
A: To form the equation you have to use one of the numbers in X (U.k Size) for this example we'll use 3 and to form the equation you have to see how much to add to X ( UK size) to get Y ( US size) and in this case it's +2.5
B: You can use the equation we just formed to get this answer by adding 2.5 to 7.5 which will give you 10