25. A and B are two alloy of copper and Tin prepared by mixing metals in proportion 7:2 and 7:11 respectively. If equal quantities of alloy are melted to form a third alloy C then find the proportion of copper and tin in alloy C.
Solution:-
∴ Proportion of copper and tin in alloy C = \(\frac{14 + 7}{4 + 11} = \frac{21}{15}\) = 7 : 5 Ans
26. Find the ratio of quantities of sugar, in which sugar costing 25 per kg and 20 per kg should be mixed so that there will be neither loss nor gain on selling the mixed sugar at the rate of 22 per kg.
Solution:-
S.P. of mixed sugar = 22 per kg
Since there is neither loss nor gain
Hence C.P. of mixed sugar = 22 per kg
Now using alligation method
27. A merchant borrowed Rs. 2500 from two money lenders. For one loan he paid 12% p.a. and for the other 14% p.a. The total interest paid for one year was Rs. 326. How much did he borrowed at each rate?
Solution:-
overall interest rate = \(\frac{326}{2500} \times 100\% = \frac{326}{25}\% \)
∴ amount given on 12% rate = \(\frac{25}{12 + 13} \times 12\) = 1200 Ans
& amount given at 14% rate = 2500-1200 = 1300 Ans