The ratio, by volume of milk to sugar to flour in a certain bread product is 3 : 15 : 20. The bread product proportions are altered so that ratio of milk to sugar is tripled while that of sugar to flour is doubled. If the altered bread contains 30 pounds of sugar, what is the ratio of milk to flour in it?

I think if the yellowed part is removed then also question stands. Its extraneous information;

given
m:s:f = 3:15:20

new product;

m'/s'= (3/15)*3 = 9/15
s'/f'= (15/20)*2 = 15/10

hence from above itself we can have

m'/f' = 9/10

hence E is correct.

Hope this helps..!!

If milk:sugar is tripled, that means that we need three times as much milk as in the original ratio. 3:15 becomes 9:15.

If sugar to flour is doubled, that means we need twice as much sugar as in the original ratio. 15:20 becomes 30:20

M:S = 9:15 = 18:30
S:F = 30:20

Since sugar is equal in both ratios, we can then see that the ratio of milk:flour is 18:20, which simplifies to 9:10

Thanks folks your answers were very useful, sometimes I get confused with the statement. In this example I wasn't able to realize that the sugar amount should remain the same (as the basis) of the recipe ratios. Cheers!