A bag has a total of 120 notes in denominations of ₹2,₹5and ₹10. The total value of the notes in the bag is ₹760. if there were twice as many ₹5 notes, the total value of the notes would be ₹960. Find the number of ₹10 notes in the bag

Ans:50 let 5 rupee notes be = X and 2 rupees notes be = Y equation will be 5X+2Y+(120-X-Y)10=760 ------ (1) if there were twice as many notes 5 rupees i.e. 2X notes of 5 rupees 2*5X+2Y+(120-X-Y)=960 --------(2) solve the both equations X=40 and Y=50. alternative: there is 200 rupee increase in total amount due to X 5 rupees note so, 5X=200 , X=40 after subtracting 40 from 120 note there will be 80 notes and amount will be 560 equation will be 2A+(80-A)10=560 8A=240 A=30 80-A = 80-30 = 50.

increase in Rs5 denomination notes caused an increase of Rs200 therefore , initially there must be 40 notes of Rs.5 denomination so, 760-200=560 remaining ,which is to be covered in more 80 qty of notes , the only possibility is 10*50 + rs2*30 =560 thus,50 answer