Answer:
Mary has £20 and Tom has £16
Step-by-step explanation:
Represent their current respective money amounts by m and t.
Then m + t = £36, but also m/2 + 2t = £42.
Multiplying the second equation by 2 removes the fraction:
m + 4t = £84
and multiplying this by -1 results in
-m - 4t = -£84, which can now be added to the first equation m + t = £36:
-m - 4t = -£84
+m + t = £36
---------------------
-3t = -£48
We have successfully eliminated m. To solve this last result for t, divide both sides by -3, obtaining t = £16
Since m + t = £36 and t = £16, m must be £20.
Mary has £20 and Tom has £16
