Average age

The average age of all people at the celebration was equal to the number of people present. After the departure of one person who was 29 years old, average age was again equal to the number present. How many people were originally to celebrate?

Result

n =  15

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

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

Next similar examples:

1. Average If the average(arithmetic mean) of three numbers x,y,z is 50. What is the average of there numbers (3x +10), (3y +10), (3z+10) ?
2. Theorem prove We want to prove the sentence: If the natural number n is divisible by six, then n is divisible by three. From what assumption we started?
3. Median and modus Radka made 50 throws with a dice. The table saw fit individual dice's wall frequency: Wall Number: 1 2 3 4 5 6 frequency: 8 7 5 11 6 13 Calculate the modus and median of the wall numbers that Radka fell.
4. Find two Find two consecutive natural numbers whose product is 1 larger than their sum. Searched numbers expressed by a fraction whose numerator is the difference between these numbers and the denominator is their sum.
5. Equation Equation ? has one root x1 = 8. Determine the coefficient b and the second root x2.
6. Evaluation of expressions If a2-3a+1=0, find (i)a2+1/a2 (ii) a3+1/a3
7. Solve 3 Solve quadratic equation: (6n+1) (4n-1) = 3n2
8. Expression with powers If x-1/x=5, find the value of x4+1/x4
9. Variable Find variable P: PP plus P x P plus P = 160
10. Holidays - on pool Children's tickets to the swimming pool stands x € for an adult is € 2 more expensive. There was m children in the swimming pool and adults three times less. How many euros make treasurer for pool entry?
11. Algebra X+y=5, find xy (find the product of x and y if x+y = 5)
12. 75th percentile (quartille Q3) Find 75th percentile for 30,42,42,46,46,46,50,50,54
13. Square root 2 If the square root of 3m2 +22 and -x = 0, and x=7, what is m?
14. Discriminant Determine the discriminant of the equation: ?
15. Roots Determine the quadratic equation absolute coefficient q, that the equation has a real double root and the root x calculate: ? Find the roots of the quadratic equation: 3x2-4x + (-4) = 0. Jo's test scores on the first four 100 point exams are as follows: 96,90,76, and 88. If all exams are worth the same percent, what is the minimum test score necessary on his last exam to earn an A grade in the class (90% or better)?