Answer:
- Mrs Spelman: 71 1/7
- Mr/Ms Murphy: 6 6/7
Step-by-step explanation:
There are no integer solutions to the problem as posed. (We suspect a typo, that the intention is 3 years from now, or that the ratio will be 5:1.)
Let m represent Murphy's age now. Then 78-m represents Spelman's age now, and the ratio in 6 years will be ...
78 -m +6 = 6(m +6)
84 -m = 6m +36 . . . . . collect terms
48 = 7m . . . . . . . . . . . . add m-36
48/7 = m = 6 6/7 . . . . . divide by the coefficient of m
Then Spelman's age now is ...
78 -m = 78 -6 6/7 = 71 1/7
Spelman is 71 1/7; Murphy is 6 6/7.
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If the ratio is 6:1 in 3 years, then Murphy is 9 and Spelman is 69.
If the ratio is 5:1 in 6 years, then Murphy is 9 and Spelman is 69.
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<em>Alternate solution method</em>
I find it easiest to add 12 years to the total (each ages by 6 years), which will give a total age of 90 in 6 years. At that time, Murphy is 1/7 of the total of ages, so dividing that sum into parts with the appropriate ratio gives m'=90/7=12 6/7; s'=77 1/7. So, m=6 6/7; s=71 1/7.
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<em>Comment on the problem</em>
We think there is a "typo" because the ratio of 6:1 means the future total should be a multiple of 7. Of course, 78+6 =84 is a multiple of 7, but adding 6 to the total will occur in 3 years, not 6 years.
