Mrs. Smith is currently 27 years older than her daughter Kate. In 8 years Mrs. Smith will be twice as old as Kate. How old are Mrs. Smith and Kate and how old will they be in 8 years?

2 Answers
Dec 19, 2017

Kate is 19 years old and Mrs. Smith is 46 years old now.

Explanation:

Suppose the age of Kate at present = xx
Then age of Mrs. Smith now = x+27x+27

Now after 8 years the age of Mrs. Smith will be twice as that of Kate.

After 8 years, the age of Kate = x+8x+8
and, age of Mrs. Smith = x+27+8x+27+8
As Mrs. Smiths's age will be twice as that of Kate after 8 years so, twice the age Kate will make it equal to Mrs. Smiths's age at that time.

Writing that in equation form,
2(x+8x+8) = x+27+8x+27+8
or, 2x + 16 = x + 352x+16=x+35

Bringing the x terms together and the number terms together

2x-x = 35-162xx=3516
or, x = 19x=19
Therefore, Mrs. Smiths's age now = x+27x+27 = 19+2719+27 = 46 years

You can check your answer by adding 8 years to both ages and see that Mrs. Smith's age is twice that of Kate after 8 years.

Dec 19, 2017

See a solution process below"

Explanation:

First, let's call Mrs. Smith's age: ss and we can call Kate's age: kk

Now we know from above Mrs. Smith is 27 years older than Kate so we can write:

s = k + 27s=k+27

We also know in 8 years Mrs. Smith will be twice as old as Kate so we can write:

s + 8 = 2(k + 8)s+8=2(k+8)

We can now substitute (k + 27)(k+27) from the first equation for ss in the second equation and solve for kk:

s + 8 = 2(k + 8)s+8=2(k+8) becomes:

(k + 27) + 8 = 2(k + 8)(k+27)+8=2(k+8)

k + 27 + 8 = (2 xx k) + (2 xx 8)k+27+8=(2×k)+(2×8)

k + 35 = 2k + 16k+35=2k+16

-color(red)(k) + k + 35 - color(blue)(16) = -color(red)(k) + 2k + 16 - color(blue)(16)k+k+3516=k+2k+1616

0 + 19 = -color(red)(1k) + 2k + 00+19=1k+2k+0

19 = (-color(red)(1) + 2)k19=(1+2)k

19 = 1k19=1k

19 = k19=k

k = 19k=19

We can now substitute 1919 for kk in the first equation and calculate ss:

s = k + 27s=k+27 becomes:

s = 19 + 27s=19+27

s = 46s=46

Mrs. Smith is 46 and Kate is 19

In 8 years Mrs Smith will be 54 and Kate will be 27