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Ratio and Proportion
The ratio of the present ages of two Friends is 2 : 3 and six years back, the ratio was 1 : 3. What will
be the ratio of their ages after 4 years ?.
Read Solution (Total 9)
-
- let the ages be 2x,3x
6yrs back,so
2x-6/3x-6=1/3
x=4
after 4 yrs
2x+4,3x+4
2(4)+4,3(4)+4
12:16
3:4 - 8 years agoHelpfull: Yes(28) No(0)
- let present age of two friends is x and y respectively
x/y=2/3 equation 1
6 yr back
(x-6)/(y-6)=1/3
3x-18=y-6
3x-y=12 equation 2
from equation 1
x=2/3y
putting the value of x in wq2
we get y=12 and x=8
this is present age after 4 yr
8+4/12/4
3/4 ANS - 8 years agoHelpfull: Yes(8) No(0)
- TRAIL AND ERROR METHOD- 2:3=8:12(PRESENT AGES)
6 YRS BACK- 1:3- (8-6):(12-6)
AFTER 4 YRS- (8+4):(12+4)= 3:4 - 8 years agoHelpfull: Yes(3) No(0)
- x/y = 2/3
x = (2/3)y
(x-6)/(y-6) = 1/3
substitute for x and solve
y = 12 and x = 8
after 4 years
y = 16 x = 12
x/y = 12/16 = 3/4.
- 8 years agoHelpfull: Yes(1) No(0)
- Two brothers ages a & b, now:
"The ratio of the present ages of two brother is 2:3
a/b = 2/3
Cross multiply
3a =2b
b=3a/2
"6 years back the ratio was 1:3."
a-6/b-6=1/3
Cross multiply
3(a-6) = b - 6
3a - 18 = b - 6
3a = b - 6+ 18
3a = b + 12
Replace with 3/2a
3a = 3/2a + 12
3a - 3/2a = 12
6a-3a/2=12
3a/2=12
a=12*2/3
a=8
then b=12
"What will be the ratio of their ages after 4 years?"
8+4/12+4=12/16=3/4; 3:4 - 6 years agoHelpfull: Yes(1) No(0)
- Ans = 3:4
x : 3/2(x)
3(x-6) : (3/2x - 6)
x = 8
- 8 years agoHelpfull: Yes(0) No(1)
- Let present age 2x , 3x
before 6 years 2x-6 and 3x-6 is equal to 1: 3
2x-6/3x-6=1/3
x=4
present ages 8 and 12
after 4 years 12 and 16
ratio 12:16
3:4 - 8 years agoHelpfull: Yes(0) No(0)
- 3:4 will be ratio of their present age
- 7 years agoHelpfull: Yes(0) No(0)
- 3:4
Let the present ages be 2X:3X
6 years ago the ages will be 2X-6/3X-6=1/3
X=4
The present ages be 2*4=8 and 3*4=12
The ratio of present ages be 8:4
After 4 years the ages will be 12:16=3:4 - 6 years agoHelpfull: Yes(0) No(0)
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