Question

divide 5600 in the ratio 4:5:7

Answer 1

When you need to split the number or a product into ratio, then consider that the sum of ratio should be equal to number/product. 

So in our case, let assume 'x' as a common factor. 
Thus,
4x + 5x + 7x = 5600;
16x = 5600;
x = 5600/16 = 350. 

So, 
4x= 350*4 =1400;
5x= 350*5 = 1750; & 
7x= 350*7 = 2450.

Your answer is, 5600 = 1400+1750+2450 which is in ratio of 4:5:7. 

Answer 2

Concept we will be using:
(i) A ratio is always expressed lowest or reduce form.
For example : 6:10= 3:5, we reduce the ratio 6:10 by cancelling both the terms by their greatest common factor 2
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The given ratio is 4:5:7

Here, the greatest common factor of the original ratio is unknown.
Let the greatest common factor be x.
Then, the original ratio will be 4x:5x:7x

Therefore, the three parts are 4x, 5x and 7x.
If we add all the parts then we must get 5600.
Then,
4x+5x+7x=5600
16x=5600
Divide both sides by 16:
x=350

Plug in the x=350 to get the three parts:
1st part = 4x =4(350)=1400
2nd part = 5x=5(350)=1750
3rd part = 7x =7(350)=2450


Answer : Required three parts are 1400, 1750 and 2450