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?

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.