adding and subtraction fractions

Question

al saves pennie. He agreed to give 1/2 of his pennies to bev if she would give him 1/2 of what she got from al to carl and if carl in turn would give 1/2 of what he got from bev to dani. bev, carl, dani agreed and dani received 15 pennies. how many pennies did al have intially?

Answer 1

Hi Louisa,

 

This an example of a "classic" word problem that requires you to work it backwards, since the only person whose actual number of pennies is the last one in the chain of sharing.  I will use A for Al, B for Bev, C for Carl, and D for Dani.

 

So:

 

D = 15.  D also = 1/2 C, so  15=1/2C, and C=30.

C=30.  C also = 1/2 B, so 30=1/2C, and B=60.

B=60.  B also = 1/2A, so 60=1/2A, and A=120

 

Al originally had 120 pennies.  That's it!  You can check your work by starting with that number at the beginning of the word problem, following all of the "halvsies," and making sure you arrive at 15 for Dani's pennies.

 

Evan