Let the cost of a bag and a pen be ₹ x and ₹ y, respectively.
Then, according to the question
3x + 4y = 257 … (i)
4x + 3y = 324 … (ii)
On multiplying equation (i) by 3 and (ii) by 4,
We get, 9x + 12y = 770 … (iii)
16x + 12y = 1296 … (iv)
Subtracting equation (iii) from (iv), we get
16x – 9x = 1296 – 771
7x = 525
x = 525/7 = 75
Hence, the cost of a bag = ₹ 75
Substituting x = 75 in equation (i), We get,
3 x 75 + 4y = 257
225 + 4y = 257
4y = 257 – 225
4y = 32
y = 32/4 = 8
Hence, the cost of a pen = ₹ 8
From the question, it’s required to find the value of (x + 10y)
⇒ 75 +10(8) = 20
Therefore, the total cost of 1 bag and 10 pens = 75 + 80 = ₹ 155.
