Question

if 18 binders bind 900 books in 10 days how many binders will be required to bind 660 books in 12 days
​

Answer 1

Answer:

11 binders

Step-by-step explanation:

we know,

work=men*days*hours

Given,

if 18 binders bind 900 books in 10 days

900 book=18 binders*10 days  ------(1)

how many binders will be required to bind 660 books in 12 days

let x be binders

660 books=x binders*12 days ---(2)

by dividing Eq(1) by (2)

900/660=18*10/x*12

x=11 binders

Answer 2

❒ Question -:

If 18 binders bind 900 books in 10 days, how many binders will be required to bind 660 in 12 days?

❒ Explanation -:

Given :

• 18 binders bind 900 books in 10 days

Need to find :

• Required number of binders to bind 660 books in 12 days

Solution :

We will solve this question using direct and indirect variation

$\small\bf \orange{\underline { \underline{\orange{ 18 \: binders \: bind \: 900 \: books \: in \: 10 \: days}}}}$

$\small\rm 1 \: binder \: binds \: 900 \: books \: in \: ( 18 × 10) \: days$

$\small\rm{ 1 \: binder \: bind \: 1 \: book \: in \: \dfrac{18 × 10}{900} \: days}$

Let us assume the required number of binders as 'x'

$\small x \small \rm{ \: binder \: bind \: 1 \: book \: in \: \dfrac{18 × 10}{900 \times \mathcal{ x}} \: days}$

$\small x \small \rm{ \: binder \: binds \: 600 \: books \: in \: \dfrac{18 × 10× 600}{900 \times \mathcal{ x}} \: days}$

It is given that x binder binds 660 books in 12 days

$\small\bf{ \dfrac{18 × 10 × 660}{900× x} = 12}$

$\small{x = {\sf \dfrac{18 × 10 × 660}{900× 12} }}$

$\small \: x \: \sf{ =\dfrac{ \cancel{ 18} \: \: \cancel{ 2}× 1 \cancel{0} × \cancel{66} \cancel{ 0} \: \: 11}{ \cancel{9} \cancel{00}× \cancel {12} \: \: \cancel{6}} }$

$\small \red{x = \sf{11}}$

The number of required binders = 11

$\rule{70pt}{2pt}$

$\star \: \large\boxed{ \underline{ { \sf{ \purple{Additional \: Information}}} }}$

Direct variation -:

• Relationship between two variables in which one is a constant multiple of the other.

Example

• The cost of books varies directly as the number of books. (more books, more cost)

Inverse variation -:

• Relationship between two variables in which the absolute value of one variable gets smaller while the other gets larger.

Example

• Time taken by a car to cover a certain distance varies inversely as the speed of the car. (More speed, less the time taken to cover the distance).

$\rule{72mm}{4pt}$