A man spends 1/3 of his salary on accomodation and 2/5 of the remainder on food. What fraction is left for other purposes?

Greetings from Brasil...

Let's find the equivalent fractions

A/B ; C/D  ⇔  A·D/B·D ; C·B/B·D

Bringing to our problem:

A/B ; C/D  ⇔  A·D/B·D ; C·B/B·D

1/3 ; 2/5  ⇔  1·5/3·5 ; 2·3/3·5  ⇔  5/15 ; 6/15

Now we can sum/add the equivalent fractions

5/15 + 6/15 = 11/15

11/15   to accomodation and food

15/15 = total

total - (accomodation and food) = other purposes

15/15 - 11/15 = 4/15

So 4/15 its the fraction for other purposes

step-by-step explanation: