If two jeans and three shirts cost Tk. 4,000 and three jeans and two shirts cost Tk. 3,500. Then how much does a pair of jeans cost?

Question: If two jeans and three shirts cost Tk. 4,000 and three jeans and two shirts cost Tk. 3,500. Then how much does a pair of jeans cost?

Solution:
ধরি,
১টি জিন্সের দাম = x টাকা
১টি শার্টের দাম = y টাকা

ATQ,
2x + 3y = 4000 -------(1)
3x + 2y = 3500 -------(2)

(1) × 3 ⇒
6x + 9y = 12000

(2) × 2 ⇒
6x + 4y = 7000

(1) - (2) ⇒
⇒ (6x + 9y) - (6x + 4y) = 12000 - 7000
⇒ 5y = 5000
⇒ y = 1000

(2) ⇒
3x + 2y = 3500
⇒ 3x + 2(1000) = 3500
⇒ 3x + 2000 = 3500
⇒ 3x = 1500
∴ x = 500

∴ ১টি জিন্সের দাম = 500 টাকা