Question

A sum of Rs 800 is in denomination of Rs 10 and Rs 20. If the total number of notes are 50.Find the number of notes of each types.

Answer 1

Answer:

Step-by-step explanation:

Let's call Rs. 10 x and Rs. 20 y:

x+y= 50  

If we subtract y from both sides we get:

x= 50-y

It makes sense, right? If I take the Rs. 20 notes out of the total of 50 notes, then I am left with just the Rs. 10 notes. So remember this value of x, we will use it in the next equation:

10x+20y= 800 Now substitute for x:

10(50-y)+20y= 800

500-10y+20y= 800 Subtract -10y+20y on left and subtract 500 on both sides:

 

 

10y= 300

y= 30 You have 30 notes of 20 Rs. and:

50-30= 20 notes of 10 Rs.

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Proof:

30(20)= 600

20(10)= 200

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Total..: 800 We have the correct answer