The sum of the ages of Dave and Ted is 48 years. Eight years from now, Ted will be three times Dave's age. Find their present age.
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Sum of ages now=48 In 8 years, sum of ages=48+16=64 Ages such that Dave is three times the age of Ted. Ted=16, Dave=48. But this is our answer for 8 years in the future so Ted current age=8, Dave current age=40
D = p r e s e n t a g e o f D a v e
T = p r e s e n t a g e o f T e d
At present: D + T = 4 8 ⟹ T = 4 8 − D ( 1 )
Eight years from now: T + 8 = 3 ( D + 8 ) ( 2 )
Substitute ( 1 ) in ( 2 ) ,
4 8 − D + 8 = 3 D + 2 4 ⟹ 5 6 = 4 D + 2 4 ⟹ 4 D = 5 6 − 2 4 ⟹ D = 8
It follows that,
T = 4 8 − 8 ⟹ T = 4 0
D=Dave's age, T=Ted's age
D+T=48, and T+8=3(D+8), which then becomes T+8=3D+24 If we solve the 2nd equation for T, we get T=3D+24-8, or T=3D+16
If we use this value to substitute T in the 1st equation, we get: D+(3D+16)=48 4D+16=48 4D=48-16 4D=32 D=32/4 D=8
This means that Dave is 8, so now we can solve for T, using: D+T=48 8+T=48 T=48-8 T=40
So Ted is 40, and Dave is 8.
Have t = T e d and d = D a v e
From the information given we can obtain two equations
t + d = 4 8
t + 8 = 3 ( d + 8 )
Re-arranging both equations to get two equations for t gives us
t + d = 4 8 ⇒ t = 4 8 − d
t + 8 = 3 ( d + 8 ) ⇒ t = 3 ( d + 8 ) − 8 ⇒ t = 3 d + 1 6
Using simultaneous equations gives us
4 8 − d = 3 d + 1 6
Simplifying this gives us a value for d
4 8 − d = 3 d + 1 6 ⇒ 3 2 − d = 3 d ⇒ 3 2 = 4 d ⇒ d = 8
Now that we have a value for d we can now work out a value for t
t = 4 8 − d ⇒ t = 4 8 − ( 8 ) = 4 0
So t = 4 0 and d = 8
Let: x = age of ted 48-x = age of dave
Therefore,
x+8 = 3(48-x+8) x+8 = 3(56-x) x+8 = 168-3x 4x = 160 x = 40
Then,
Age of ted is 40 years old and 8 years old is the age of dave...
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Sum of ages now=48
In 8 years, sum of ages will be =48+16=64
as Ted will be 3 times as old as Dave.that means their age's ratio will be =3:1
now, 4 6 4 = 1 6
so, Teds age will be = 1 6 × 3 = 4 8 and Daves age will be = 1 6 × 1 = 1 6 years old
so, current age of Ted is = 4 8 − 8 = 4 0 years old and current age of Dave is= 1 6 − 8 = 8 years old