Question

O EQUATIONS AND INEQUALITIESSolving a word problem with three unknowns using a linear...

Answer 1

Given:

The sum of three numbers is 81, The third number is 2 times the second, The first number us 9 moe than the second.

Required:

We need to find all the numbers

Step-by-step explanation:

Assume that a, b and c are the first, second and third numbers respectively.

By given ststement

`\begin{gathered} a+b+c=81\text{ .....\lparen i\rparen} \\ c=2b\text{ .....\lparen ii\rparen} \\ a=b+9\text{ .....\lparen iii\rparen} \end{gathered}`

substitute c and a in equation (i)

`\begin{gathered} b+9+b+2b=81 \\ 4b=72 \\ b=18 \end{gathered}`

now put value of b in equation (ii) and (iii)

`c=2*18=36`

and

`a=18+9=27`

FInal answer:

first number a = 27

second number b = 18

third number c = 36