500 grams of salt solution has 20% salt in it. How much salt should be added to make 60% in the solution?

Question: 500 grams of salt solution has 20% salt in it. How much salt should be added to make 60% in the solution?

Solution:
Amount of salt = 500 × 20/100
= 100 grams
Let,
x gram salt to be added

ATQ,
(100 + X)/(500 + X) = 60%
⇒ (100 + X)/(500 + X) = 60/100
⇒ (100 + X)/(500 + X) = 3/5
⇒ 5(100 + X) = 3(500 + X)
⇒ 5X + 500 = 3X + 1500
⇒ 5X - 3X = 1500 - 500
⇒ 2X = 1000
∴ X = 500 grams