now let start with 8 kg of solution y
so liquid x=30%of 8 kg =2.4 kg
water=70 % of 8 kg=5.6 kg

now after this water remaining =5.6 -2=3.6 kg
liquid x remain umnchanged at 2.4 kgs
now 2 kg of solution is added so water added will be 70% of 2=1.4 kg
liquid x will be 30 % of 2 =0.6 kg
so present concentration
liquid x 2.4(initially)+0.6 newly added=3 kg
water= 3.6+1.4=5 kg
liquid x % in liquid y now is (3/8)*100= 75/2= 37 1/2 % i.e option c