Problem On Ages:
1. The ratio between the ages of M and N is 5:6 respectively. If the ratio between the one-third age of M and half of N's age is 5:9, then what's the age of N ?
Solution:
Let their ages will be 5x and 6x respectively.
If the ratio between the one-third age of M and half of N's age is 5:9
Then,
1/3(5x) / 1/2(6x) = 5/9
9*(1/3)*(5x) = 5*(1/2)*(6x)
3*5x = 5*3x
15x = 15x
Thus, N's age can't be determined.
2. Ten years ago, A was half of B in age. If their ratio of their present ages is 3:4, what will be the total of their present ages ?
Solution:
Let the ages(ten years ago) of A and B are x, 2x respectively.
Their present ages will be (x+10) and (2x+10) respectively.
Hence,
(x+10)/(2x+10) = 3/4
4(x+10) = 3(2x+10)
4x+40 = 6x+30
10 = 2x
x = 5
The sum of their present ages = (x+10)+(2x+10) = 15+20 = 35 years.
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