you can use any data set in this table (except the row with x) to get the ratio.
so 20/196 is the ratio which equals about .102041
then multiply that decimal by the weight in the x row to see what x is
so 1078(.102041) = 110.000198 just round that to 110. you can also verify that ratio by checking other data points. for instance
490(.102041) = 50.00009 or 50
so you know x is 50 so answer is either b or d
then you know the ratio .102041, so does (10/98) = .102041
or does (98/10) = .102041
if you do the division you will see that (10/98) = .102041
so the answer is D