Question

A lady bought 8 pencil ,5eraser for rupee 21 to give 5children but when she visit there were 9children. She bought 3 pencil and 4 eraser for rupee 10 find the price of one pencil and one eraser

Answer 1

let price of pencil be ₹x and price of eraser be ₹y
(i) 8x + 5y = 21
(ii) 3x + 4y = 10

(i)×4:
32x + 20y = 84
(ii)×5:
15x + 20y = 50

(i) - (ii):
(32x + 20y) - (15x + 20y) = 84 - 50
17x = 34
x = 2

substituting value of x:
3×2 + 4y = 10
4y = 10 - 6
4y = 4
y = 1

therefore a pencil costs ₹2 and an eraser ₹1

Answer 2

therefore price of 1 pencil is ₹2 and 1 eraser is ₹1.