Question

a sum of Rs.800 is in the form of denominations of rs.10 and rs. 20 ...if the total no. of notes is 50, find the number of notes of each type ....with process​

Answer 1

Answer:

30 rs.20 notes; 20 rs.10 notes

Step-by-step explanation:

Let rs. 10 = x, rs. 20 = y

The amount of notes there are in all is 50, while the sum if $800. Set the system of equation:

x + y = 50

10x + 20y = 800

First, isolate the variable x in the first equation. Note the equal sign, what you do to one side, you do to the other. Subtract y from both side:

x + y (-y) = 50 (-y)

x = 50 - y

Plug in 50 - y for x in the second equation.

10(50 - y) + 20y = 800

Simplify. Distribute 10 to all terms within the parenthesis.

10(50 - y) = (10)(50) - (10)(y) = 500 - 10y

500 - 10y + 20y = 800

Simplify. Combine like terms.

500 (-10y + 20y)  = 800

500 + 10y = 800

Isolate the variable y. Note the equal sign, what you do to one side, you do to the other. Do the opposite of PEMDAS. (PEMDAS = Parenthesis, Exponents (& Roots), Multiplication, Division, Addition, Subtraction). Remember to follow the left - > right rule still.

Subtract 500 from both sides.

10y + 500 (-500) = 800 (-500)

10y = 800 - 500

10y = 300

Isolate the variable y. Divide 10 from both sides.

(10y)/10 = (300)/10

y = 300/10

y = 30

y = 30

Plug in 30 for y in the second equation.

10x + 20y = 800

10x + 20(30) = 800

Simplify. Combine like terms and isolate the variable x.

10x + 600 = 800

Isolate the variable x. Note the equal sign, what you do to one side, you do to the other. Do the opposite of PEMDAS. First, subtract 600 from both sides.

10x + 600 (-600) = 800 (-600)

10x = 800 - 600

10x = 200

Next, divide 10 from both sides.

(10x)/10 = (200)/10

x = 200/10

x = 20

x = 20

30 rs.20 notes; 20 rs.10 notes is your answer

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