Question

While solving questions in unitary method we first find unit value and then multiply them with another no..
To find unit value is there is any formula? Answer fast...(90 points)

Answer 1

1. 2 balls cost $ 8. Find the cost of 3 balls.

Cost of 2 balls = $ 8

Cost of 1 ball = $ 8 ÷ 2 = $ 4

Cost of 3 balls = $ 4 × 3 = $ 12

2. Cost of 1 book is $ 20. What is the cost of 10 such books?

Cost of 1 book = $ 20

Cost of 10 books = $ 20 × 10

                       = $ 200

3. 12 oranges cost $ 72. Find the cost of 4 oranges.

Cost of 12 oranges = $ 72

Cost of 1 orange = $ 72 ÷ 12 = $ 6

Cost of 4 oranges = $ 6 × 4 = $ 24

4. Cost of 5 pens is $ 125. What is the cost of 1 pen?

Cost of 5 pens = $ 125

Cost of 1 pen = $ 125 ÷ 5

                   = $ 25

5. 6 pens cost $ 96. How much will 2 such pens cost?

Cost of 6 pens = $ 96

Cost of 1 pen = $ 96 ÷ 6 = $ 16

Cost of 2 pens = $ 16 × 2 = $ 32

6. Cost of 10 note books is $ 250. Find the cost of 15 note books.

Cost of 10 note books = $ 250

Cost of 1 note book = $ 250 ÷ 10

                            = $ 25

Cost of 15 note books = $ 25 × 15

                              = $ 375

7. Cost of 5 chocolate is $ 15. Find the cost of 10 chocolate.

Cost of 5 chocolates= $15

Cost of 1 chocolate = $15 ÷ 5

                            = $ 3

Cost of 10chocolate = $ 3× 10

                            = $ 30

8. Cost of 8 balls is $ 16. Find the cost of 17 balls.

Cost of 8 balls = $ 16

Cost of 1 ball = $ 16 ÷ 8

                   = $ 2

Cost of 17 balls = $ 2× 17

                      = $ 34

Answer 2

$\mathfrak{Answer:}$

$\mathbb{UNITARY\;METHOD:}$

• The method of finding first the value of one quantity from the value of given quantities and then the value of required quantities .

$\mathbb{TYPES\;OF\;VARIATION:}$

1. Direct variation :

• If one increases then other also increases .
• If one decreases then other also decreases.
• Ratio of quantities remain same.

$\bold{x\propto y}\\\\\tt{then}\\\\\\\tt{\dfrac{x_1}{y_1}=\dfrac{x_2}{y_2}.}$

     2. Inverse variation :

• If one increases then other decreases .
• If one decreases then other increases.
• Product will be same as x₁ × x₂ = y₁ × y₂

$\bold{x\propto\dfrac{1}{y}}\\\\\tt{then}\\\\\\\tt{\dfrac{x_1}{y_1}=\dfrac{y_2}{x_2}}.$