A bag contains Rs.20, Rs.10, Rs.5 notes in the ratio 3:4:5. If the bag contains Rs.1,000 in total, then the number of Rs.5 notes is:

Correct option is D

Let the number of ₹20, ₹10, and ₹5 notes be 3x3x3x, 4x4x4x, and 5x5x5x, respectively.
The total value of the notes:
Value of ₹20 notes = 3x×20 = 60x
Value of ₹10 notes = 4x×10 = 40x
Value of ₹5 notes = 5x×5 = 25x
Total value = 60x+40x+25x =125x
the total value to ₹1,000:
125x=1000
x = 8
The number of ₹5 notes is:
5x=5×8=40