At first, Tim : Dave = 4 : 3. Let Tim = 4u, Dave = 3u.<br>
After Tim saves $12 and Dave spends $12:<br><br>
[[model:questions/solutions/q5410.png]]<br><br>
&bull; Tim after = 4u + 12, Dave after = 3u − 12<br>
&bull; Ratio after is (4u + 12) : (3u − 12) = 6 : 1<br>
&bull; 4u + 12 = 6(3u − 12)<br>
&bull; 4u + 12 = 18u − 72<br>
&bull; 14u = 84 → u = 6<br>
&bull; Tim at first = 4 × 6 = $24<br>
<br>
Tim had $24 at first.<br>
Check: Tim $24, Dave $18. After: Tim $36, Dave $6. 36 : 6 = 6 : 1. ✓