Classs mean

Class size is 30 students, math was not worse than sign 2. Determine the number of pupils who were sign 1 if the class had a 1.4 sign average.

Result

a =  18

Solution:

a+b= 30
a+2b = 1.4 *30

a+b = 30
a+2b = 42

a = 18
b = 12

Calculated by our linear equations calculator.

Leave us a comment of this math problem and its solution (i.e. if it is still somewhat unclear...): Be the first to comment! To solve this verbal math problem are needed these knowledge from mathematics:

Looking for help with calculating arithmetic mean? Looking for a statistical calculator? Do you have a linear equation or system of equations and looking for its solution? Or do you have quadratic equation?

Next similar math problems:

1. Exam average Average of marks that have on the certificates students of 8.A class in mathematics is exactly 2.45. If we did not add 1 and 3 of sutdents Michael and Alena, who arrived a month ago, it would average exactly 2.5. Determine how many students have class 8.
2. Summerjob Three students participated in the summerjob. Altogether they earn 1780, -. Peter got a third less than John and Paul got 100,- more than Peter. How much got every one of them?
3. Blackberries Daniel, Jolana and Stano collected together 34 blackberries. Daniel collected 8 blackberries more than Jolana, Jolana 4 more than Stano. Determine the number blackberries each collected .
4. Three brothers The three brothers have a total of 42 years. Jan is five years younger than Peter and Peter is 2 years younger than Michael. How many years has each of them? Number 118 divide into two addends, so first addend is 69 greater than 75% of the second addend.
6. Fifth of the number The fifth of the number is by 24 less than that number. What is the number?
7. Football season Dalibor and Adam together scored 97 goals in the season. Adam scored 9 goals more than Dalibor. How many goals scored each?
8. Football match 4 In a football match with the Italy lost 3 goals with Germans. Totally fell 5 goals in the match. Determine the number of goals of Italy and Germany.
9. Two numbers We have two numbers. Their sum is 140. One-fifth of the first number is equal to half the second number. Determine those unknown numbers.
10. Spain vs USA Spain lost to the US by 4 goals. In the match total fell 10 goals. How many goals gave the Spain and how the United States?
11. Substitution solve equations by substitution: x+y= 11 y=5x-25
12. Trees Along the road were planted 250 trees of two types. Cherry for 60 CZK apiece and apple 50 CZK apiece. The entire plantation cost 12,800 CZK. How many was cherries and apples?
13. Equations Solve following system of equations: 6(x+7)+4(y-5)=12 2(x+y)-3(-2x+4y)=-44
14. Hotel rooms In the 45 rooms, there were 169 guests, some rooms were three-bedrooms and some five-bedrooms. How many rooms were?
15. Simple equation Solve for x: 3(x + 2) = x - 18
16. Parking 120 vehicles parking on the morning. Pasenger car is charged 20 CZK, 50 CZK per bus. The guard collected for parking 2640 CZK in total. How many cars and how many buses stood in the parking?
17. 13 tickets A short and long sightseeing tour is possible at the castle. Ticket for a short sightseeing circuit costs CZK 60, for a long touring circuit costs CZK 100. So far, 13 tickets have been sold for 1140 CZK. How much did you pay for tickets for a short tour?