An artist packs his kit with 3 tools. his choice is limited to pencils and brushes.

the list shows all of the combinations of kits by selection order (first, second, third). p stands for pencil, and b stands for brush.

ppp, ppb, pbp, pbb, bpp, bpb, bbp, bbb

what is the probability that he will have only one pencil if he were to pick from the kit at random from the list shown?

round the answer to the nearest hundredths.