Answer:
a = 1.2, b = 2
Explanation:
In this case, variables a and b must add up to 3.2, and a must be divided by b to get 0.6. This is what the colon symbol means.
Since 12 / 2 is equal to 6, we can use this knowledge to divide 12 by 10 to get 1.2. If we add 2 + 1.2, we get 3.2, and if we divide 1.2 by 2, we get 0.6.