math

posted by .

a man saved a sum of 200 dinars in the first month, 250 in the second month, 300 in the third month and he continue to save at the streght. after how many month can he buy a radio instronment coastin 13500 dinars

  • math -

    arithmetic series
    a = 200
    d = 50

    Sum(n) = (n/2)[2a + (n-1)d]
    13500 = n/2 [400 + 50(n-1)]
    27000 = n(50n + 350)
    50n^2 + 350n - 27000 = 0
    10n^2 + 7n - 5400 = 0
    n = ..... One answer will be + , the other -, reject the -

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. math 101

    Write and answer the hidden question. Then solve. 1. Gloria talked on her cell phone for 320 minutes the first month, 243 minutes the second month, and 489 minutes the third month. Her payment package does not allow her to pay per …
  2. Algebra

    Monthly Budget: You earn $250 per month from your part-time job. You are in a kayaking club that costs $20 per month, and you save at least $100 each month. Write and solve an inequality to find the possible amounts you have left to …
  3. math

    Gloria talked on her cell phone for 320 minutes the first month, 243 minutes the second month and 489 minutes the third month.Her payment package does not allow her to pay per minute;she can only buy packages.If she has to pay $25 …
  4. math

    Xuan saved $5340 in 3 years. If he saved $95 per month in the first year and a fixed amount per month for the next 2 years, how much did he save per month during the last 2 years?
  5. Algebra 2

    After one month at a new job you decide to save $50. Each month you plan to increase your savings by five dollars. a.)Write an explicit formula to model the amount you will save each month. b.)How much will you save in the seventh …
  6. Algebra

    After one month at a new job you decide to save $50. Each month you plan to increase your savings by five dollars. a.)Write an explicit formula to model the amount you will save each month. b.)How much will you save in the seventh …
  7. Math

    If a salesman sold 2 cars in his first month, 8 cars in his second month, and 32 cars in his third month, using the same sequence how many cars would he sell in month 4, month 5, and month 6
  8. Algebra

    You earn $250 per month from your part-time job. You are in a kayaking club that costs $20 per month, and you save at least $100 each month. Write and solve an inequality to find the possible amounts you have left to spend each month.Can …
  9. math

    Gloria talked on her cell phone for 320 minutes the first month, 243 minutes the second month, and 489 minutes the third month. Her payment package does not allow her to pay per minute; she can only buy groups of minutes. If she has …
  10. math

    diego is saving money to buy a computer game. he saves $2 the first month , and each month after that, he saves twice as much as the previous month. which expression shows how much he saves in the third month

More Similar Questions