Question 3178
Let total income be x

Then income spent on:

:rent=x/3
:food=x/4
:clothes:x/5

Total fraction spent
={{{x/3+x/4+x/5}}}
={{{(20x+15x+12x)/60}}}
=47/60x

Therefore,fraction which is left
= 13/60x which is equal to 39 pounds

Therefore,
13x=39*60
x=(39*60)/13
x=3*60
<br>
x=180 pounds (total income)
<P>
<b>weekly income of 180 pounds</b>