Question

The cost of 15 kg tea and coffee is Rs. 183 and the cost of 25 kg tea and 13 kg coffee is Rs 213. What will be the cost of 7 kg tea and 1 kg coffee?

Answer 1

HI there !!

Let the cost of 1 kg tea be x and the cost of 1 kg coffee by y

You have not mentioned the kg of coffee in case 1 ,
i have taken the weight of coffee as 15 kg
15x + 15y = 183            ---> [1]

also ,
25x + 13y = 213                ---> [2]

lets make the coefficients of x equal .


5 x (15x + 15y = 183 ) => 75x + 75y = 915 ---> [3]

3 x (25x + 13y = 213  ) => 75x + 39y = 639   ---> [4]

subtracting (3) - (4)

75x + 75y = 915
 75x + 39y = 639
=========
36 y = 276

y = 7.6 ≃ 8

15x + 15y = 183

15x + 135 = 183

15x = 48

x = 3.2 ≃ 3

x = 3 , y = 8 

these are just approximate values !