A boy has rs728 in denomination of rs 2 notes, rs 5 notes and rs 10 notes in the ratio of 3:2:4, respectively. What is the total number of notes he has?

(A)104 (B)127
(C)100 (D)117

Add up the value of each kind of note:

2(3x)+5(2x)+10(4x) = 728

now find x, and the total number of notes is

3x+2x+4x = 9x

or, see how much 1 set of 9 notes is worth: 2*3+5*2+10*4 = 56

728/56 = 13

So there are 13 sets of 9 notes...

117

To find the total number of notes the boy has, we need to find the number of notes in each denomination.

Let's assume the number of rs 2 notes is 3x, the number of rs 5 notes is 2x, and the number of rs 10 notes is 4x, where x is a common factor.

Since the total value of all the notes is rs 728, we can set up the equation:

(2 * 3x) + (5 * 2x) + (10 * 4x) = 728

Simplifying the equation:

6x + 10x + 40x = 728
56x = 728
x = 728 / 56
x ≈ 13

Now we can find the number of notes in each denomination:

Number of rs 2 notes = 3x ≈ 3 * 13 = 39
Number of rs 5 notes = 2x ≈ 2 * 13 = 26
Number of rs 10 notes = 4x ≈ 4 * 13 = 52

The total number of notes he has is 39 + 26 + 52 = 117.

Therefore, the answer is (D) 117.