Answer: Option A
To find out how much Monica spent on the fourth day, we can use the formula for calculating the average, which is:
Average = (Sum of values) / (Number of values)
We know that Monica's average expenses for 4 days is Rs. 6.0, so we can write:
6.0 = (Sum of expenses) / 4
Multiplying both sides by 4, we get:
Sum of expenses = 24
We also know that Monica spent Rs. 7.70 on the first day, Rs. 6.30 on the second day, and Rs. 10 on the third day. So the total amount she spent on these three days is:
7.70 + 6.30 + 10 = 24.00
Subtracting this amount from the sum of expenses for all 4 days, we can find how much she spent on the fourth day:
24.00 - 24 = 0
Therefore, Monica spent Rs. 0 on the fourth day. The correct option is A, Rs. 0.
In conclusion, we used the formula for calculating the average to find out the sum of expenses for all 4 days. We then subtracted the sum of expenses for the first three days from the total to find out how much she spent on the fourth day. Since the result was zero, we can conclude that Monica did not spend any money on the fourth day.