HELP ME PLEASE!!!!

Question

Boxes X and Y each contained some pebbles. There were 3 more pebbles in Box X than in Box Y. After Erika moved 5 pebbles from Box X to Box Y, there were 20 pebbles in Box Y. How many pebbles were in Box X in the beginning.

PLEASE HELP ME!

Answer 1

Let's define some equations here. We know that there are 3 more pebbles in Box X than in Box Y:

X = Y + 3

We know that Erika moved 5 pebbles from Box X and ADDED them to Box Y. Therefore, we now have:

X - 5 pebbles in Box X and Y + 5 pebbles in Box Y.

We know that Box Y has 20 pebbles AFTER the 5 pebbles were added to it:

Y + 5 = 20

Solving for Y, we get:

Y = 15

Plugging into our original equation, X then becomes:

X = 15 + 3

X = 18

To check our answer, we know that in the beginning, Box X had 3 more pebbles than Box Y. 18 is 3 more than 15, so this checks out. We know that after she took 5 pebbles from Box X, she ADDED it to Box Y and ended with a total of 20. 15 + 5 = 20, so this also checks out.