Joshua is five years older than david. simon is four years older than joshua and nine years older than david. simon's and david's ages added together equal 15. what is the age of joshua?
Kent, melcor, and jerick went on a hike, carrying a bag of guavas. they stopped for a nap. kent woke up, ate 1/3 of the guavas and went back to sleep. later, melcor wake up and ate 1/3 of the remaining guavas and went back to sleep. finally, jerick woke up and ate 1/3 of the remaining guavas. there are now 8 guavas left in the sack. how many guavas had been there originally?