Question

The cost of 11 pencils and 3 erasers is rupees 50 and the cost of 8 pencils and 3 erasers is rupees 38. Find the cost of 5 pencils and 5 erasers​

Answer 1

Answer:

assume X is cost of pencil

and Y is cost of erasers

let we write it as

11x + 3y = 50 ••••••• eq 1

8x + 3y = 38. •••••••eq 2

subtract on both side

3x + 0 = 12

3x = 12

x = 12/3

x = 4

put x = 4 in eq 1

11 (4) + 3y = 50

44 + 3y = 50

3y = 6

y = 2

the cost of 1 pencil = Rs.4

the cost of 1 eraser = Rs.2

therefore

the cost of 5 pencil = 5 x 4 = Rs.20

the cost of 5 pencil = 5 x 2 = Rs.10