How many kgs of wheat costing Rs.24/- per kg must be mixed with 30 kgs of wheat costing Rs.18.40/- per kg so that 15% profit can be obtained by selling the mixture at Rs.23/- per kg?
20
15
10
12
Explanation:
S.P. of 1 kg mixture = Rs.23. Gain = 15%.
CP of 1 kg mixture = Rs. [(100/115) x 23] = Rs.20
Let the quantity of wheat costing Rs.24 is x kgs.
Using weighted average rule = ($x$×24+30×18.4)/ (x+30) =20
On Solving, we get x = 12.