A shop keeper bougth rice of Rs. 30 at a rate of Rs. 1.5 per kg and of Rs. 30 at a rate of Rs. 4 per kg. Then what is the value of mixed rice per kg ?

Explanation

Here , the total amont of buying price of the shopkeeper = Rs. (30+30)=Rs.60
The quantity of the total rice boughtb
`=(30)/(1.5)+(30)/(4)kg =2+7(1)/(2) kg =27(1)/(2) kg `
`therefore ` the price of the mixed rice per kg =Rs. `(60)/(27(1)/(2))`
`=Rs. (60)/((55)/(2))=Rs. (24)/(11)` =Rs. 2.18 (approx.)
`therefore ` The required rate of price =Rs. 2.18 per kg .
We can also find the result by using harmonic mean. According to the formula,
the H.M.`=(2)/((1)/(15)+(1)/(4))=(2)/((1)/(1(1)/(2))+(1)/(4))=(2)/((2)/(3)+(1)/(4))`
`=(2)/((8+3)/(12))=(2xx12)/(11)=(24)/(11)=2.18`
`therefore ` the average price of rice =Rs. 2.18 per kg.