A lending library has a fixed charge for the first three days and an additional charge for each day thereafter. Geeta paid Rs.27 for book kept for seven days while Mohit paid Rs.21 for the book he kept for five days .Find the fixed charges and charge for each extra day.(linear equations)
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Answered by
8
Let the fixed charge be x
and additional charge be y
3x+4y=27.....................(i)
in second case
3x+2y=21..................(ii)
from equation (i) & (ii)
3x+4y=27.......(i)
3x+2y=21........(ii)
- - -
__________
subtractin (ii) from (i)
2y =6
y=6÷2
y=3
putting the value of y in equ. (i)
3x+4y=27
3x+4×3=27
3x+12=27
3x=27-12
3x=15
x=15÷3
x=5
and additional charge be y
3x+4y=27.....................(i)
in second case
3x+2y=21..................(ii)
from equation (i) & (ii)
3x+4y=27.......(i)
3x+2y=21........(ii)
- - -
__________
subtractin (ii) from (i)
2y =6
y=6÷2
y=3
putting the value of y in equ. (i)
3x+4y=27
3x+4×3=27
3x+12=27
3x=27-12
3x=15
x=15÷3
x=5
Meghinie:
So when you find the value of x so you put it in 2nd eq
??
you can put the value of x in either the first or second equ.
thanks
wait so will it change the answer
the final answer
no it doesn't change the answer
I see thanks
the given answer is the final answer
Answered by
2
Let the fixed charge be X
Extra charge be y
As per the condition
X+7y=27-----------------1
X+5y=21------------------2
From 1 and 2 ,by elimination method we get
2y=48
y=24
Sub y=24 in 1
X+7(24)=27
X=-174
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