Math help - Average

[matrix07012]

I need help with a math task.

 

25% of customers bought product A for 25€.

40% of customers bought product B for 50€.

35% of customers bought product C for 60€.

 

How do I calculate the average money spend?

[Dash Lambda]

Just add of the prices by portion.

To calculate a normal average you add up each value and divide by the number of items, so since you have percentage, you can treat it as 100 items. Instead of dividing the summation by 100, you can simplify it by changing the percentages to their decimal forms, so your calculation is just adding up each price multiplied by its portion.

[LAwLz]

Not sure if this is the best way of doing it, but here is how I'd solve this.

 

Assume that there are 100 customers.

 

25 of them paid 25 euro. 25 * 25 = 625

40 of them paid 50. 40 * 50 = 2000

35 of them paid 60. 35 * 60 = 2100

 

Now let's add them all together.

625 + 2000 + 2100 = 4725

 

 

4725 is what they all paid in total, but we want to find the average. To find the average we take the total amount paid, and then divide by the number of people who bought the product. We had 100 people, so we divide by 100.

 

4725/100 = 47,25

 

Answer: 47,25 euro

 

 

 

If we want to double check, we can change from 100 customers to 1000. We should get the same result in the end.

250 paid 25. 250*25 = 6250

400 paid 50. 400*50 = 20000

350 paid 60. 350*60 = 21000

 

6250+20000+21000 = 47250

 

47250/1000 = 47,25