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Two positive numbers x and y are in the ratio a : b where 0 < a < b. If x + y = c then find the smaller of x and y in terms of a, b and c. Please leave explanation too please! :)

 Nov 1, 2015

Best Answer 

 #1
avatar+23254 
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If x and y are in the ratio a:b, then x:y  =  a:b  or  x/y  =  a/b.

Since  x + y  =  c,  then  y  =  c - x..

Since  x/y  =  a/b  and  y  =  c - x, then, by substituting:  x/(c - x)  =  a/b.

Cross multiplying:  x(b)  =  a(c - x)   --->   bx  =  ac - ax   --->   ax + bx  =  ac   --->   x(a + b)  =  ac

Dividing both sides by  (a + b)   --->   x  =  ac / (a + b)

 Nov 2, 2015
 #1
avatar+23254 
+15
Best Answer

If x and y are in the ratio a:b, then x:y  =  a:b  or  x/y  =  a/b.

Since  x + y  =  c,  then  y  =  c - x..

Since  x/y  =  a/b  and  y  =  c - x, then, by substituting:  x/(c - x)  =  a/b.

Cross multiplying:  x(b)  =  a(c - x)   --->   bx  =  ac - ax   --->   ax + bx  =  ac   --->   x(a + b)  =  ac

Dividing both sides by  (a + b)   --->   x  =  ac / (a + b)

geno3141 Nov 2, 2015

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