Final answer:
To find the ratio a:b given that a+b=4a, we rearrange the equation to find b=3a, and then simplify the ratio to get 1:3.
Step-by-step explanation:
To find the ratio a:b, given that a+b=4a, we first need to express b in terms of a. This can be done by subtracting a from both sides of the equation:
a + b - a = 4a - a
b = 3a
Now that we have b expressed as 3a, we can find the ratio of a to b:
a : b = a : 3a
As we can simplify the ratio by dividing both terms by a (assuming a is not zero):
a : b = 1 : 3
Therefore, the ratio of a to b is 1:3.