Question

Three children collected a total of 270 used books. Clare collected 25 more books then Ryan. Jerry collected 19 more used books than Clare. How many used books did Jerry collect?

Answer 1

You can set equations here;

C stands for Clare
R stands for Ryan
J stands for Jerry

C + R + J = 270

C =  25 + R  
J = 19 + C 

So our goal is to solve for J.

Start by isolating R; we can do that on second equation.
C - 25 = R

Now plug that in first equation;

C + (C-25) + J = 270

Now we need to isolating C; we can do that on third equation;

J-19 = C
Plug that in equation we recently work on;

(J-19) + ( (J-19)-25 ) + J = 270

Simplifying;

(J-19) + (J-44) + J = 270
 J+J+J - 19 - 44 = 270
3J - 63 = 270

Now solve for J;

3J = 333

J = 111

So Jerry collected 111 used books.