So there's 200 grams of juice in a cup juice is 40 % while water is 60 % how much % juice would be if poured 200 grams of water more ?
There will be the same AMOUNT of juice after dilution, BUT the PERCENTAGE will change:
Original AMOUNT 200gm x 40% = 80 gm
AFTER DILUTION there will be 80gm in 400gm= 80gm/400gm x 100% = 20% juice