Question 1177751
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Choose an arbitrary age for the son that will make the calculations easier: suppose the son's age is 10.  Then<br>
320% of 10 = 10(3.20) = 32<br>
320% OLDER THAN 10 = 10+32 = 42<br>
The ratio of their ages is 10:42 = 5:21 = 1:4.2<br>
If you understand percent increases, you don't have to go through all those calculations.  An increase of 320% = 3.2 means the original number is multiplied by 1+3.2 = 4.2; the ratio is 1:4.2.<br>