4%of the selling price of an article is equal to 5% of its cost price. Again 20% of the selling price is Rs.120 more than 22%ofits cost price. The ratio ofcostprice & selling price is

let Selling price be SP , Cost price be CP

4% of SP = 5% CP

SP =$$\frac{5}{100}\times \frac{100}{4}$$CP = $$\frac{5}{4}$$CP 

SP = $$\frac{5}{4}$$CP ---------> using this in the below equation

20% of SP = 120 + 22% of CP

$$\frac{20}{100}\times$$ $$\frac{5}{4}$$CP = 120 +22% CP

$$\frac{1}{4} $$CP = 120 + $$\frac{22}{100} $$CP

$$\frac{1}{4}$$CP - $$\frac{22}{100} $$CP  = 120

$$\frac{3}{100} $$CP = 120

CP = 4000

SP = $$\frac{5}{4}\times$$ 4000 = 5000

CP :SP = 4000:5000 = 4:5