Question

.the sum of three numbers is 124. if the ratio between the first and second be 4 : 9 and that between the second and third be 1 : 2. find the difference between the third number and the sum of first and second number.

Answer 1

Let the first number be 'x'
Let the second number be 'y'
Let the third number be 'z'
Given that
x:y = 4:9
=> x=4y/9
Given that
y:z = 1:2
=> z=2y
Given that
x+y+z=124----------(1)
Substitute values of x and y in equation (1)
=> (4y/9)+y+2y = 124
=> (4y+9y+18y)/9 =124
=> 31y/9 =124
=> y = 124 * (9/31)
=> y = 4*9
y=36
z=2y=2(36)=72
x=4y/9 =(4*36)/9=16
=> z-(x+y) = 72-(16+36) = 72-52 = 20
Therefore the answer is 20
Hope it helps.