The ratio of the present ages of two brothers is 4:5. Five yrs ago the ratio of the square of their ages was 9:16. Find their present ages.
Answers
Answer:
Let the brothers' ages be x and y.
Then x:y = 4:5
By cross-multiplication...
5x=4y
5x-4y = 0
After 10 years, their ages will be x+18 and y+10
(x+10):(y+10) = 6:7
By cross-multiplication...
7x+70 = 6y+60
7x-6y+10 = 0
Multiplying the first equation by 3 and the sexond equation by 2 and subtracting ...
15x-12y = 0
14x-12y = -20
-.... +........ +
__________
x = 20
5×20 = 4×y
y = 25
The elder brother is 25 years old now, so after 15 years he will be 40 years old.
Answer:
20,25
Step-by-step explanation:
The ratio of the present ages of 2 brothers is 4:5
The ratio of the square of the ages of 2 brothers 5 years ago is 9:16
The ratio of the ages of 2 brothers 5 years ago is 3:4
4x-5 : 5x-5 = 3x : 4x [Compare]
4x-5 = 3x
x = 5
5x-5 = 4x
x = 5 [Confirmed]
their present ages are 4x,5x
their present ages are 4(5) , 5(5)
their present ages are 20,25
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