• Решите, пожалуйста, задание! Очень нужно!

    The sum of ages of Tom and Elizabeth is 49. Tim is twice as old as Elizabeth was when Tom was as old as Elizabeth is now. How old are they?

Ответы 1

  • We have two moments of history here: "now" and "then" (at particular moment in the past). Let's mark as the following:T - Tom's age nowE - Elizabeth's age nowTo - Tom's age thenEo - Elizabeth's age thenSo we have:T - E =  To - Eo (their difference is constant)   (1)T + E = 49                                                         (2)T = 2Eo                                                            (3)To = E                                                               (4)Using (4) into (1): T - E =  E - Eo  Then using (3) here:2Eo - E =  E - Eo  2Eo + Eo =  E + E3Eo =  2EE = 3/2 Eo                                                         (5)Using (5) and (3) into (2):T + E = 492Eo + 3/2Eo = 49  3 1/2Eo = 497/2Eo = 49Eo = 49 : 7/2Eo = 14So, Elizabeth was 14. It means now Tom is 2*14=28. Elizabeth now is 49 - 28 = 21Answer: Elizabeth is 21, Tom is 28
    • Автор:

      rustymjup
    • 6 лет назад
    • 0
  • Добавить свой ответ

Еще вопросы

Войти через Google

или

Забыли пароль?

У меня нет аккаунта, я хочу Зарегистрироваться

How much to ban the user?
1 hour 1 day 100 years