1.

Radha paid Rs. 920 for 4 earphones and 12 charging chords, while Rukmini paid Rs. 980 for 6 earphones and 10 charging chords. Find the cost of 5 earphones and 11 charging chords.1. Rs. 8902. Rs. 9703. Rs. 9504. Rs. 880

Answer» Correct Answer - Option 3 : Rs. 950

Let price per earphone be Rs. x and price per charging chord be Rs. y

According to question,

4x + 12y = 920      ----(1)

6x + 10y = 980      ----(2)

By equation (1) × 3 – equation (2) × 2,

⇒ 12x + 36y – 12x – 20y = 2760 – 1960

⇒ 16y = 800

⇒ y = 50

Put the value of y in eq. (1)

∴ 4x + 12 × 50 = 920

⇒ 4x = 920 – 600

x = 320/4 = 80

Now, Cost of 5 earphones and 11 charging chords = 5 × 80 + 11 × 50 = Rs. 950

∴ Cost of 5 earphones and 11 charging chords is Rs. 950

Short Trick: 

Let price per earphone be Rs. x and price per charging chord be Rs. y

According to question,

4x + 12y = 920      ----(1)

6x + 10y = 980      ----(2)

Add equation (1) and (2) 

4x + 12y + 6x + 10y = 1900

⇒ 10x + 22y = 1900

⇒ 2(5x + 11y) = 1900

⇒ 5x + 11y = 950

∴ Cost of 5 earphones and 11 charging chords is Rs. 950


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