Three numbers are A, B and C are in the ratio 1 : 2 : 3 and their average is 600. If A is increases by 10% and B is decrease by 20%, then the average increased by 5%, C will be increase by :

Let A ,B and C respectively = $$x , 2x , 3x$$

=> Sum of A , B and C = $$x + 2x + 3x = 3 \times 600$$

=> $$6x = 1800$$

=> $$x = \frac{1800}{6} = 300$$

=> $$A = 300 , B = 600 , C = 900$$

Value of A after increment = $$\frac{110}{100} \times 300 = 330$$

Value of B after increment = $$\frac{80}{100} \times 600 = 480$$

New value of average = $$\frac{105}{100} \times 600 = 630$$

Acc to ques,

=> $$\frac{330 + 480 + C'}{3} = 630$$

=> $$810 + C' = 3 \times 630 = 1890$$

=> $$C' = 1890 - 810 = 1080$$

$$\therefore$$ C is increased by = 1080 - 900 = 180