Homework Question

[xud]

Hi all, I was helping my son with homework tonight and had a total brain freeze.
Here's the question:

Mina has 5 more marbles than Kirsty
Kirsty has 2 more marbles than Seb
Altogether they have 30 marbles.
How many does each child have?

I just can't figure out how to work it out.

[elliemay1]

IMO Prudie's method is the easiest to follow.

[elliemay1]

^ Prudie for Best Answer!

[Mamyalynne]

Of course Prudie is right , I was responding to the huge paragraph above.

Prud?

[jourdain2]

I'm burbling quietly in a corner and reciting 'Jabberwocky' to myself!

[mazie]

I had to learn that and stand up on stage in assembly and recite Jabberwocky when I was 8 joudain...Seemed very daunting at the time!

[Togo]

Love Prudie's answer but would have gone for Mina has X +7. Almost explains itself then.