Q. A man gets Rs. 100 per day if he works, but he is fined by Rs. 10 per day if he is absent.
In the whole month of April he received Rs. 1900 only. How many days did he work ?
Adding (i) and (iii),
Let the number of days the man was present be ‘x’ and the number of days he was absent be ‘y’.
According to first condition,
100x
= 1900
According to second condition,
x
= 30 ......(ii)
Multiplying (ii) by 10
10x + 10y
= 300 .....(iii)
100x – 10y
= 1900
10x + 10y
= 300
110x
= 2200
∴ x
= 20
∴ The man worked for 20 days.
Sol.
What do we need to be find ?
We don’t know absent days
We don’t know present days
Lets understand this statement with the help of example
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Present
Days
20
22
30
x
Amt. Received
Per Day
100
100
100
100
Total Amt.
Received
20 × 100
22 × 100
30 × 100
x × 100
10y
–
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Absent
Days
2
5
8
y
Fine
Per Day
10
10
10
10
Total Fine
Paid
2 × 10
5 × 10
8 × 10
y × 10
Total salary received is Rs 1900
......(i)
Total salary =
amount received – total fine paid
In this sum we are talking about april month
April has how many days?
30 days…ie total of present and absent days should be altogether 30
+
y
Lets solve it by equating the coefficient method
Lets make the coefficient of y same