Question

Lisa is 10 cm taller than her friend ian. Ian is 14 cm taller than jim. Every month, their heights increase by 2 cm. In 7 months, the sum of ian's and jim's height will be 170 cm more than lisa's height. How tall is ian now?

Answer 1

Answer: Ian's height = x+14 = 69+14 = 83 cm

Explanation :

Let the height of Jim be x

Let the height of Ian be x+4

Let the height of Lisa be x+4+10=x+14

Since their heights increase by 2cm every months

so after 7 months ,

Jim's height = x+14

Ian's height= x+4+14=x+18

Lisa's height= x+14+14=x+28

According to question,

Sum of Ian's and Jim's height = 170cm

`x+18+x+14 = 170\\2x+32 =170\\2x =170-32\\2x = 138`

⇒x =
`(138)/(2)`

⇒ x= 69cm

∴ Ian's height = x+14 = 69+14 = 83 cm

Answer 2

Ian is 194 cm tall now

Explanation:

Let the height of Jim be x

Now we are given that Ian is 14 cm taller than jim.

So,height of Ian be x+14

Now we are given that Lisa is 10 cm taller than her friend ian.

So, height of Lisa be x+14+10=x+24

Since their heights increase by 2 cm every months

So after 7 months ,

Jim's height =
`x+(7 *2)=x+14`

Ian's height=
`x+14+(7 *2)=x+28`

Lisa's height=
`x+24+(7 *2)=x+38`

Now we are given that In 7 months, the sum of ian's and jim's height will be 170 cm more than lisa's height.

So,
`x+14+x+28=x+38+170`

`x+42=208`

`x=208-42`

`x=166`

So, Ian's height = x+28 =166+28 = 194 cm

Hence Ian is 194 cm tall now