Unknown number

15% of the unknown number is 18 less than 21% of the same number. What is the unknown number?

Correct answer:

x =  300

Step-by-step explanation:


0.15x + 18 = 0.21 x

0.15•x + 18 = 0.21•x

0.06x = 18

x = 300

Our simple equation calculator calculates it.



We will be pleased if You send us any improvements to this math problem. Thank you!



avatar




Tips to related online calculators
Our percentage calculator will help you quickly calculate various typical tasks with percentages.
Do you have a linear equation or system of equations and looking for its solution? Or do you have a quadratic equation?

You need to know the following knowledge to solve this word math problem:

Related math problems and questions:

  • Energy saving
    energy_star They were released three different, independent inventions saving 20%, 24% and 15% energy. Some considered that while the use of these inventions, the total savings will be 20% + 24% + 15% = 59%. Is this true? How much percent of energy will save all thre
  • Unknown number 7
    percents2_9 16% of the unknown number is by 21 less than unknown number itself. Determine the natural unknown number.
  • Cinema tickets
    listky Cinema sold 180 tickets this Thursday, which is 20%. Monday 14%, Tuesday 6%, Wednesday 9%, Friday 24%, Saturday 12%, and Sunday 15%. How many tickets were sold per week?
  • Unknown number x
    percents2_4 5% from an unknown number equals the number 26. What is the unknown number?
  • Speed of Slovakian trains
    zssk_train Rudolf decided to take the train from the station 'Ostratice' to 'Horné Ozorovce'. In the train timetables found train Os 5409 : km 0 Chynorany 15:17 5 Ostratice 15:23 15:23 8 Rybany 15:27 15:27 10 Dolné Naštice 15:31 15:31 14 Bánovce nad Bebravou 15:35 1
  • 3 years
    ekonomicky-rast The company has increased the number of employees. In year 2005 compared to 2004 13% more, in 2006 18% more against the previous year, in year 2007 20% more compared to 2006. How many % increase in the number of employees in 3 years?
  • Reducing number
    123 Reducing the an unknown number by 28.5% we get number 243.1. Determine unknown number.
  • Unknown number 24
    numbs_6 f we add 20, we get 50% of its triple. What is this unknown number?
  • If we
    math_4 If we increase the unknown number by 4%, we get 780. Determine the unknown number.
  • Four numbers
    equilateral_triangle_5 The first number is 50% second, the second number is 40% third, the third number is 20% of the fourth. The sum is 396. What are the numbers?
  • 15% of
    bank2 15% of the revenue from sales was CZK 24,000 and it had to be written off as sales tax. What was the net profit on sales?
  • Unknown number 5
    seven I think of an unknown number. If we enlarge it five times then subtract 3 and the result decreases by 75% we get one greater than the number. What number am I thinking of?
  • Crowns
    money_4 1180 crowns are divided into three people: A got 20% less than B and C by 15% more than B. How many got A, B, and C?
  • Sum of three numbers
    bulb2_4 The sum of three numbers from which second number is 20% smaller than the first number and the third number is 25% smaller than the second number is 96. Determine this numbers.
  • Unions now
    roh The plant has 1,250 employees. The Trade Unions (former ROH, OH) is 18% male, 23% female. Plant management reported that in the trade union is 20% of all employees. How many men and women are in the plant, and how many are men and women in trade unions?
  • School year
    boys_girls At the end of the school year has awarded 20% of the 250 children who attend school. Awat got 18% boys and 23% of girls. Determine how many boys and how many girls attend school.
  • CuSO4 mixture
    chemia_2 How many grams of solid CuSO4 we have to add to 450g of 15% CuSO4 solution to produce a 25% solution?