Question

3 kg of potatoes and 4 kg of carrots have a total cost of 440p.
4 kg of potatoes and 3 kg of carrots have a total cost of 470p.

Work out the total cost of 1 kg of potatoes and 1 kg of carrots.

Answer 1

let us assume that cost of 1kg potatoes is x
and cost of 1kg carrot be y
according to 1 condition
3x +4y=440
acc to condition 2
4x +3y=470
you have now multiply 1by 4 and 2by 3
then add them

Answer 2

3x+4y=440

4x+3y=470

Adding and subtracting the both equations

7x+7y=910

-x-7y=-30

Solving the two equations

x=30-7y

Substituting the X value in the first equation

90-21y+4y=440

90+17y=440

17y=350

y=20.588

using y finding the x

3x+4 * 20.588 = 440

3x=440-82.35

3x = 357.64

x=119.21

Cross Check : 3 * 119.21 + 4 * 20.588 = 440 Approx