Q.

Solve the pair of equation by using the substitution method: 0.2x+0.3y=1.3;0.4x+0.5y=2.3.


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a

x=-3and y=-2

b

x=2and y=2

c

x=3and y=2

d

None of these 

answer is C.

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Detailed Solution

Given equations are:
0.2x+0.3y=1.3………….(1)
0.4x+0.5y=2.3……………(2)
From equation (i), we get,
0.2x=1.3-0.3y x=13-3y2…………………(3)
Substituting x=13-3y2  in equation (2),
0.413-3y2+0.5y=2.3
2.6-0.6y+0.5y=2.3
-0.1y=-0.3
y=3
Substituting y=3 in equation (3),
x=13-3×32
x=2
Therefore, option (3) is correct.
 
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