How many kg of sugar costing Rs 5.75 per kg should be mixed with 75 kg of cheaper sugar costing Rs 4.50 per kg so that the mixture is worth Rs 5.50 per kg ?

 Let the quantity of sugar = x

By the rule of mixture and Alligation,

Type A                                                            Type B

x                                                                        75

5.75                                                                   4.50

                                5.50

1.00                                                                   0.25

$$\frac{x}{1.00}$$ = $$\frac{75}{0.25}$$

x = $$\frac{75  \times 1}{0.25}$$

x = 300 Kg