If old packet contained 520g and new packet contains 1/5 less, then the new packet has 80% of the old packet
80% = 0.8
520 x 0.8 = 416g
20% = 0.2 = 104g
520 x 0.2
416 + 104 = 520
So the new packet contains 416g of coffee.
1.6m questions
2.0m answers