Let’s learn how to convert a situation into an expression.

 

First

      we find variable in our situation

      and then make an expression.

Situation

Variable

Expression

Sarita has 10 more
marbles than Ameena.

Let

Marbles with Ameena = x

Marbles with Sarita

           = x + 10

Balu is 3 years
younger than Raju

Let

Raju’s Age = x years

Balu’s age

       = (x − 3) years

Bikash is twice
as old as Raju.

Let,

Raju’s age = x years

Bikash’s age

  = 2 × 𝑥

        = 2x years

Raju’s father’s age is 2 years more than 3 times Raju’s age.

Let

Raju’s Age = x years

Raju’s father's age

       = (3x + 2) years

How old will Susan
be 5 years from now?

Let,

Susan’s Age = y years

Susan’s age
after 5 years

       = (y + 5) years

How old was Susan
4 years ago ?

Let,

Susan’s Age = y years

Susan’s age
4 years ago

     = (y − 4) years

Price of wheat per kg is rupees 5 less

Let,

 Price of rice per kg

= p Rupees

Price of wheat per kg

      = (p − 5) rupees

Price of oil per litre
is 5 times the price of rice per kg.

Let,

 Price of rice per kg

     = p Rupees

Price of oil per litre

= 5p rupees

The speed of a bus is
10 km/hour more than
the speed of a truck
going on the same road.

Let,

Speed of truck

  = y km/hr

Speed of bus

= (y + 10) km/hr

Ali has twice as much apps as Nandan do.

Let,

Number of apps
with Nandan = x

No. of apps

with Ali = 2x

Rajshri has got 3 more certificates than Kamal.

Let,

 No: of certificates
that Kamal has = x

No: of certificates that Rajshri has

  = x + 3

Anthony has 10 toys less than Kabir

Let,

Number of toys with Kabir = x

Let,

Number of toys Anthony have = x - 10

Sumit's weight is one-third of his grandfather's weight

Let,

Weight of Sumit’s grand father = w

Weight of Sumit

  = w/3

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.