Answer and explanation:
The ratio 1:2 is different from the ratio 2:1. The ratio 1:2(one to two) means a comparison of two sizes; the ratio of one part of that thing to the ratio of two parts of that thing. Likewise, the ratio 2:1 is the comparison of two parts of a thing to the ratio of one part of the thing. For the ratio 2:1, we could say for example that for every two crushed tomatoes there is one tomato paste.