Skip to main contentSkip to solution

A mixture of coffee and cocoa, 16% of which is coffee, costs Rs 240 per kg. Another mixture of coffee and cocoa, of which 36% is coffee, costs Rs 320 per kg. If a new mixture of coffee and cocoa costs Rs 376 per kg, then the quantity, in kg, of coffee in 10 kg of this new mixture is

Solution

✅ Correct Option: 4

Let coffee cost cc Rs/kg and cocoa cost kk Rs/kg.

From the two mixtures:

0.16c+0.84k=240⋯(1)0.16c + 0.84k = 240 \quad \cdots(1)

0.36c+0.64k=320⋯(2)0.36c + 0.64k = 320 \quad \cdots(2)


(2)−(1)(2) - (1):

0.20c−0.20k=800.20c - 0.20k = 80

c−k=400⋯(3)c - k = 400 \quad \cdots(3)

Substituting c=k+400c = k + 400 in (1)(1):

0.16(k+400)+0.84k=2400.16(k + 400) + 0.84k = 240

0.16k+64+0.84k=2400.16k + 64 + 0.84k = 240

k=176k = 176 Rs/kg

c=176+400=576c = 176 + 400 = 576 Rs/kg


Let the fraction of coffee in the new mixture =f= f

576f+176(1−f)=376576f + 176(1 - f) = 376

576f+176−176f=376576f + 176 - 176f = 376

400f=200400f = 200

f=12f = \dfrac{1}{2}


Coffee in 10 kg of the new mixture =12×10=5= \dfrac{1}{2} \times 10 = 5 kg

The answer is Option 4: 55

Keyboard Shortcuts

  • Left arrow: Previous question
  • Right arrow: Next question
  • S key: Jump to solution
  • Q key: Jump to question