Given:
lemon juice = 60% in the bottle
water = 1 liter.
Since lemon juice is 60% and the rest is water. Water is 40% of the bottle.
1 liter of water is equivalent to 40% of the bottle.
1/40% = 2.50 liters amount of total liquid in the water.
2.50 x 60% = 1.5 liters of lemon juice.
0.6x + 0.4x = 2.5