Weighted average - Examples, Exercises and Solutions

What is Michael's score if he gets 79 on the first exam and 83 on the second, given that the weight of the first test is 30% and that of the second is 70%?

To solve the weighted average, we will use the following formula:

exam 2 * weight of evaluation 2 + exam 1 * weight of the evaluation 1 = Weighted average

We will place the data in the formula, where the weights will be in decimal numbers:

0.3*79 + 0.7*83 = 
23.7+58.1 = 

81.8

$81.8$

Norbert buys some new clothes.

When he gets home, he decides to work out how much each outfit cost him on average.

4 t-shirts = $45 <br>2 pairs of shorts =$50
3 pairs of pants = $80<br>2 sweaters =$100
1 coat = $210

What answer should he come up with?

$77.5

The hotel's rating is determined by several factors, each with a different weight. Here is the rating for the "Happy Tourist" hotel:

Satisfaction: 50% 4.5

Cleanliness: 30% 4

Customer service: 10% 5

Breakfast: 10% 3

What is the hotel's rating?

4.25

What is the average grade of the student who got the following:

68 on an exam that represents 40%.

73 on an exam that represents 20%.

94 on a project that represents 15%.

91 on homework that represents 25%.

$78.65$

What is Monica's average grade if she gets 98 on an assignment that represents 30% and a 95 on an exam that represents 70%?

$95.9$

A number of hotels are ranked based on various factors, each with a different weight.

This is the rating and weights for the hotel "The Swan Inn":

Satisfaction: 3.5 (45%)
Cleanliness: 4 (30%)
Customer Service: 2 (10%)
Breakfast: 4.5 (10%)
Pool: 1 (5%)

What is the hotel's overall rating?

3.475

A company is making an advertisement for a new roller coaster and they want to know what the weighted average of its travel speed is.

100 km/h 20%
40 km/h 15%
130 km/h 5%
60 km/h 35%
15 km/h 5%
75 km/h 20%

What is the average speed of the roller coaster?

69.25 km/h

There are 45 students in a class, 20 of whom have 2 siblings, 15 of whom have 1 sibling, while the rest have no siblings.

How many siblings do the students in the class have on average?

$1.22$ siblings

A teacher wants to calculate Gabriel's final weighted average.

The following are Gabriel's exam results:

84 on the test, which is 30% of the final grade.

73 on the exam, which is 15% of the final grade.

87 on the test, which is 35% of the final grade.

92 on the project, which is 20% of the final grade.

What is Gabriel's final average?

$85$

Ramiro applies to a high school where the average grade required for mathematics is 85.

The following are Ramiro's grades on his maths exams:

92 on a final exam that represents 40%.

78 on a project that represents 15%.

98 on a quiz that represents 10%.

83 on an exam that represents 35%.

Will Ramiro be admitted to the high school and what is his grade average?

Yes, $87.35$

A factory produces a mix of feathers for filling pillows that constitutes 42% pigeon feathers, 32% goose feathers, and the rest are ostrich feathers.

The prices of the feathers per kg are:

Pigeon - $35 </p><p>Goose -$95

Ostrich - $72

What is the price per kg of the mix?

\( 63.82

A teacher loses the final exam results of one of his students. Luckily for him, he had already calculated the student's average grade for this year.

Attendance: 95 (10%)
Assessment: 82 (10%)
Assignments: 100 (20%)
Final exam: ??? (60%)

If the student's average is 92, then what grade did he get on his final exam?

90.5

A durable alloy is made of iron and aluminum.

30% of the alloy is aluminum costing $5 per 100 grams, while 70$17 per 100 grams.

What is the price of 100 grams of the alloy?

$13.4$ $

Below are the data from a factory quality control:

Over 3 days they found 4 defective items each day.

Over 2 days they found 7 defective items each day.

Over 1 day there were no defective items at all.

Over 10 days there were 18 defective items each day.

How many defective items are there on average each day?

$12.875$

Ivan rolls a dice and records the results:

$4,3,1,6,5,3,1$

What is the average number resulting from the dice rolls?

$3.29$