Ana's age exceeds one-fifth of her dad's age by seven. In 19 years, her dad will be twice as old as her. How old is her dad now?
Pls, help! I think it is 17.5 or 19, but I'm not sure. :(
4 answers
Pls Help!
A = d/5 + 7 ... 5A = d + 35 ... d = 5A - 35
2(A + 19) = d + 19 ... 2A + 38 = d + 19 ... d = 2A + 19
substituting ... 5A - 35 = 2A + 19
solve for A , then substitute back to find d
2(A + 19) = d + 19 ... 2A + 38 = d + 19 ... d = 2A + 19
substituting ... 5A - 35 = 2A + 19
solve for A , then substitute back to find d
Now:
dad's age --- x
Ana's age --- y
y - x/5 = 7
y = x/5 + 7
Ana's age ---- (1/5)x + 7
19 years from now:
dad = x+19
Ana's age = (1/5)x + 7 + 19 = x/5 + 26
x+19 = 2(x/5 + 26)
x+19 = 2x/5 + 52
times 5, (don't like fractions)
5x + 95 = 2x + 260
3x = 165
x = 55
Her dad is now 55
check:
now her dad is 55
Ana is now 55/5 + 7 or 18 years
in 19 years:
dad is 74+19 = 74
ana = 18 + 19 = 37 , YES, here dad will be twice as old
dad's age --- x
Ana's age --- y
y - x/5 = 7
y = x/5 + 7
Ana's age ---- (1/5)x + 7
19 years from now:
dad = x+19
Ana's age = (1/5)x + 7 + 19 = x/5 + 26
x+19 = 2(x/5 + 26)
x+19 = 2x/5 + 52
times 5, (don't like fractions)
5x + 95 = 2x + 260
3x = 165
x = 55
Her dad is now 55
check:
now her dad is 55
Ana is now 55/5 + 7 or 18 years
in 19 years:
dad is 74+19 = 74
ana = 18 + 19 = 37 , YES, here dad will be twice as old
a = Ana"s present age
d = dad's present age
Ana's age exceeds one-fifth of her dad's age by seven means:
a = d / 5 + 7
After 19 years Ana’s age will be a + 19 and Dad’s age will be d + 19
In 19 years, her dad will be twice as old as her means:
d + 19 = 2 ( a + 19 )
Since a = d / 5 + 7 replace
a with d / 5 + 7 in this equation
d + 19 = 2 ( d / 5 + 7 + 19 )
d + 19 = 2 ( d / 5 + 26 )
d + 19 = 2 d / 5 + 52
Subtract 19 to noth sides
d = 2 d / 5 + 33
Subtract 2 d / 5 to both sides
d - 2 d / 5 = 33
5 d / 5 - 2 d / 5 = 33
3 d / 5 = 33
Divide both sides by 3
d / 5 = 11
d = 55
a = d / 5 + 7 =
55 / 5 + 7 = 11 + 7 = 18
Ana is 18 yrs , Dad is 55 yrs old
d = dad's present age
Ana's age exceeds one-fifth of her dad's age by seven means:
a = d / 5 + 7
After 19 years Ana’s age will be a + 19 and Dad’s age will be d + 19
In 19 years, her dad will be twice as old as her means:
d + 19 = 2 ( a + 19 )
Since a = d / 5 + 7 replace
a with d / 5 + 7 in this equation
d + 19 = 2 ( d / 5 + 7 + 19 )
d + 19 = 2 ( d / 5 + 26 )
d + 19 = 2 d / 5 + 52
Subtract 19 to noth sides
d = 2 d / 5 + 33
Subtract 2 d / 5 to both sides
d - 2 d / 5 = 33
5 d / 5 - 2 d / 5 = 33
3 d / 5 = 33
Divide both sides by 3
d / 5 = 11
d = 55
a = d / 5 + 7 =
55 / 5 + 7 = 11 + 7 = 18
Ana is 18 yrs , Dad is 55 yrs old