Question

a man has rs.150 in notes of 10 rupee and 5 rupee. if the number of 5 rupee notes is three times that of 10 rupee notes, how many of each kind does the man have?

Answer 1

Let the number of notes of 10₹ be x
For 5₹ be y
10x+5y=150
also
y=3x
Therefore
10x+5(3x)=150
25x=150
x=6
put x=6 in eq
y=3x
=3(6)
=18
Hope it helps....
:)

Answer 2

Hi there!
Here's the answer:

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Let No. of 10₹ notes = x
and No. of 5₹ notes = y

Given,
(No. of 5 ₹ notes) = 3 × (No. of 10 rupee notes)

=> y = 3×x
=> y = 3x

Now,
Total sum of Rupees the Man has = 150₹

{ Note that sum of Rupees = (No. of Notes) × (Value of Note) }

(x × 10₹) + (3x× 5₹) = 150₹
10x₹ + 15x₹ = 150₹
=> 25x₹ = 150₹
=> x = (150/25)
=> x = 6

•°• No. of 10₹ notes x= 6
and No. of 5₹ notes y= 3x= 3×6 = 18.


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Verification:

Sum of Notes = 150₹
6 10₹ Notes => 60₹
18 5₹ Notes => 90₹
Adding both, we get
150₹

•°• Given data matched.

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:)
Hope it helps