Question

Solve the pair of equations by using the substitution method.
0.2x + 0.3y = 13
0.4x + 0.5y = 2.3

Answer 1

Hi,

It is given that ,

0.2x + 0.3y = 1.3

=> 0.3y = 1.3 - 0.2x

y = ( 1.3 - 0.2x )/0.3 ----( 1 )

0.4x + 0.5y = 2.3 ---( 2 )

substitute equation ( 1 ) in equation ( 2 ),

we get

0.4x + 0.5[( 1.3 - 0.2x )/0.3] = 2.3

0.12x + 0.65 - 0.1x = 2.3 × 0.3

0.02x = 0.69 - 0.65

0.02x = 0.04

x = 0.04/0.02

x = 2

substitute x = 2 in equation ( 1 ) ,

we get

y = [ 1.3 - 0.2 × 2 ]/0.3

y = ( 1.3 - 0.4 )/0.3

y = 0.9/0.3

y = 9/3

y = 3

Therefore ,

x = 2 and y = 3

I hope this helps you.

: )