the average sales about car per day dealer is 5.if sales on to consecutive days for 21 and 17 car respectively .then average goes up to 7. find how many days was the average calculated earlier
Answers
Given :
Average car per day is 5 cars
sales of next two days is 21 & 17
Average after two days is 7 cars
To Find :
No. of days for which average was calculated initially
Solution :
•let n be the number of days for which average calculated earlier
•Average is equal to Number of cars per day
i.e. Average = (Sum of cars sold in n days)/n
5n = sum of cars sold in n days
____________(1)
•For next two days :
Sales :- Day 1 = 21
Day 2 = 17
•Now, total number of days are n+2
Average =( sum of cars sold in n+2 days )/(n+2)
7(n+2) = sum of cars sold in n+2
days
7n + 14 = sum of cars in n days +
sum of cars in next two days
7n + 14 = 5n + 21 + 17
2n = 24
n = 12
•Earlier average was calculated for 12 days .
Answer:
12
Step-by-step explanation:
12 days was the average