Class 6 Maths Algebra | Using Expressions Practically |

__Using Expressions Practically__

__The use of expressions comes handy in everyday. For e.g. if we know that the price of one kg onion is Rs.5 less than the price of 1kg potato, then we can use expressions to calculate the price of 1kg onion. Let the price of 1kg potato be __*x. *Then the price of 1kg onion if Rs. (*x*-5).

Similarly, if Seema is 5 years older than Ritu and the age of Ritu is given to be *z years. *Then Seema’s age is (*z* + 5) years.

__Examples:__

__Problem: Answer the following:__

Take Sarita’s present age to be *y . *

What will be her age 5 years from now?

Her age 5 years from now will be = (*y +5)* years.

What was her age 3 years back?

Her age 3 years back was = (*y* – 3) years.

Sarita’s grandfather is 6 times her age. What is the age of her grandfather?

Age of Sarita’s grandfather = (6**y) *years

Grandmother is 2 years younger than grandfather. What is grandmother's age?

Age of Sarita’s grandmother = (Age of grandfather – 2) years

= (6**y* -2) years

Sarita’s father’s age is 5 years more than 3 times Sarita’s age. What is her father's age?Age of Sarita’s father = (3*y* + 5) years.

__A rectangular box has height __*h * Its length is 5 times the height and breadth is 10 cm less than the length. Express the length and the breadth of the box in terms of the height.

Height of rectangular box = h cm. (given)

Length of rectangular box = 5*h cm

Breadth of rectangular box = (Length – 10) cm

= (5*h -10)cm.

A bus travels at *v *km per hour. It is going from Daspur to Beespur. After the bus has travelled 5 hours, Beespur is still 20 km away. What is the distance from Daspur to Beespur? Express it using *v*.

Speed of the bus = *v *km per hour

Distance travelled in 5 hours = Speed*Time

= Speed (km per hour)* 5 hours

= 5*v *kms

Distance from Daspur to Beespur =Distance travelled in 5 hours + 20km

= (5*v *+ 20)kms

.