In a cupboard there are pencils, rulers and books. The number of pencils is 15 more than that of rulers. The number of books is three time that of rulers. If the number of pencils is p, which one the total number of items in the cupboard?

Answer 1

p = 15 + r where p = pencils and r = rulers.

b = 3r where b = books

total number of items = p + b + r =
15 + r + 3r + r =

15 + 5r.

p - 15 + 3(p-15) + p is how you express in terms of p.

p - 15 + 3p - 45 + p =

5p - 60 is the total in terms of p.