Надо срочно! Дано: a:b= 7/12:7/3 b:c=8:14/3 c:d=1:2 (a+b+c+d) : 4 = 9 Найти: a-? b-? c-?...

Question

Надо срочно!
Дано:
a:b= 7/12:7/3
b:c=8:14/3
c:d=1:2
(a+b+c+d) : 4 = 9
Найти:
a-? b-? c-? d-?

Answer 1

A:b = 7*3/(7*12) = 0,25 => a = 0,25b

b:c = 8*3/14 = 12/7 => b = 12c/7

c:d = 0,5 => c = 0,5d

a = 0,25b = 0,25*12c/7 = 3c/7 = 3*0,5d/7 = 1,5d/7

b = 12c/7 = 12*0,5d/7 = 6d/7

a + b + c + d = 1,5d/7 + 6d/7 + 0,5d + d = 36

(7,5 + 3,5 + 7)d/7 = 36

18d = 36*7
d = 14

c = 0,5d = 7

b = 6d/7 = 12

a = 1,5d/7 = 3

Ответ: 3; 12; 7; 14

Comments

Спасибо большое.

Answer 2

A : b = 7/12 : 7/3
a : b = 1/4
b = a : 1/4 = 4a
-------
b : c = 8 : 14/3
b : c = 24/14 = 12/7
c = b : 12/7 = 7b / 12
c = ( 7 • 4a ) / 12 = 28a/12 = 7a/3
---------
c : d = 1 : 2
d = c : 1/2
d = 2c
d = 2 • ( 7a/3 ) = 14a / 3
---------
( a + b + c + d ) : 4 = 9
a + b + c + d = 36
( a + 4a + ( 7a / 3 ) + ( 14a / 3 ) ) = 36
( 3a + 12a + 7a + 14a ) / 3 = 36
36a = 36 • 3
a = 3
b = 4 • 3 = 12
c = ( 7•3 ) / 3 = 7
d = ( 14•3 ) / 3 = 14

Comments

Спасибо . Этот вариант тоже учту.